Criminal Defense Lawyers

Can The FBI Track My Phone After A Subpoena – What Federal Investigators Can Actually See

You received a federal subpoena. Maybe it demanded documents, maybe it requested your testimony, maybe it sought records from your business. But now you’re wondering something else entirely: can they track my phone? Are federal agents monitoring where I go, who I call, where I sleep at night? The answer is more disturbing than a simple yes or no – because by the time you’re asking this question, they may already have years of your location history sitting in an evidence file.

Here’s what nobody tells you about federal phone surveillance: the subpoena you received might be completely unrelated to the phone tracking that’s already happened. Federal investigators don’t need to subpoena YOU to get your phone records. They subpoena your carrier directly. AT&T, Verizon, T-Mobile – these companies receive thousands of law enforcement requests and comply with most of them without ever notifying you. The first sign that investigators have your phone data might be when a prosecutor reads your location history aloud at trial.

And here’s the uncomfortable truth that should terrify anyone under federal investigation: your phone has been generating a permanent record of everywhere you’ve been for years. Every cell tower your phone connected to, every location ping, every movement pattern – all of it stored by your carrier and available to investigators who know how to request it. AT&T keeps this data for seven years. That means investigators can reconstruct where you were on any given day going back the better part of a decade. Your phone has been testifying against you long before you knew you were under investigation.

What The FBI Can Get Without A Warrant

Let me explain exactly what federal investigators can obtain with just a subpoena – no warrant required, no judge evaluating probable cause.

With a simple administrative subpoena, the FBI can get your subscriber information:

• Your name and billing address
• How you pay your bill
• How long you’ve had the service
• Your device’s electronic serial number – the unique identifier that distinguishes your phone from every other phone in the world
• Your IP addresses, showing which networks your phone has connected to

Heres the thing about this “basic” information. Its not basic at all. Your subscriber information tells them exactly who you are and were you live. Your IP addresses show were you access the internet. Your device serial number lets them track that specific phone across multiple data sources. This information becomes the foundation for everything else they request.

The subpoena creates a roadmap for the warrant application. Once investigators have your subscriber information, they know exactly which carrier holds your detailed records. They know your phone number, your account history, your device identifiers. This makes the warrant application for your actual location data almost a formality – they already know were to look and what to ask for.

Think about the sequence. The FBI dosent need to suspect you of anything specific to issue a subpoena for subscriber information. They just need your phone number. Once they have that basic information, they build the probable cause showing for a warrant using other evidence. The subpoena starts the process; the warrant completes it. By the time your asking wheather they can track your phone, theyve probably already obtained the records.

What Requires A Warrant – And The Carpenter Decision That Changed Everything

In 2018, the Supreme Court decided United States v. Carpenter, and the decision changed how federal investigators obtain cell phone location data. Understanding this case helps you grasp what protections you have – and what massive loopholes remain.

Before Carpenter, prosecutors argued that cell phone location data wasnt protected by the Fourth Amendment. There theory was simple: you voluntarily share your location with your phone company every time your phone connects to a cell tower. Since you shared the information voluntarily, you had no reasonable expectation of privacy in it. Investigators could get your location history with just a court order under the Stored Communications Act – a much lower standard then a warrant.

The Carpenter case involved 127 days of cell site location information. One hundred twenty-seven days of data showing were the defendant went, when he went there, and how long he stayed. The Supreme Court said this was too much. “Historical cell site location information reveals the privacies of life,” the Court wrote. It requires a warrant based on probable cause.

Heres what Carpenter actualy requires now. Federal investigators need a warrant – supported by probable cause and approved by a judge – to obtain historical cell site location information. This includes tower data showing which cell sites your phone connected to, when it connected, and for how long. Its a significant protection.

But Carpenter left massive holes in the protection:

• The decision specifically addressed historical cell site location information
• It didnt address real-time tracking
• It didnt address tower dumps – requests for information about every phone that connected to a particular tower at a particular time
• And it definately didnt address what happens when investigators simply buy location data from commercial data brokers instead of requesting it from carriers

The Tower Dump Problem Nobody Discusses

The FBI has a specialized team called CAST – the Cellular Analysis Survey Team. A 139-page internal FBI guide obtained through FOIA reveals exactly how this team operates. And one of there most powerful tools is something called a tower dump.

A tower dump is a request for information about every cell phone that connected to a particular cell tower during a particular time period. Not just your phone – every phone. If investigators beleive a crime occurred at a specific location, they can request data on everyone who was there. Your phone just happened to connect to that tower while you were driving past? Your information is now in the hands of federal investigators.

Tower dumps capture innocent people constantly:

• Drive past the scene of a bank robbery on your way to work? Your phone might be in that tower dump
• Walk by a location were drug deals occur? Your phone might be flagged
• The connection between your phone and the investigation might be pure coincidence – but now investigators have your information and can examine it for other evidence

Heres whats disturbing about tower dumps. The Carpenter decision required warrants for historical location data on a specific target. But tower dumps are different – there requesting data on thousands of phones simultaneously. Courts have been inconsistent about what legal process is required. Some courts require warrants; others allow broader requests. The law hasnt caught up to the technology.

And once investigators have tower dump data, they can identify phones of interest and then seek warrants for those specific devices. The tower dump becomes a fishing expedition that identifies targets. Its exactly the kind of general warrant the Fourth Amendment was supposed to prohibit.

The Stingray Secret The FBI Doesnt Want You To Know

Theres another way federal investigators track phones that dosent involve carriers at all. Its called a Stingray – or more generically, a cell site simulator – and the FBI has been using them since at least 1995.

A Stingray device pretends to be a cell phone tower. Your phone, looking for the strongest signal, connects to the fake tower instead of a real one. Once connected, the Stingray can identify your phone, track your location in real time, and in some versions, intercept your communications. You have no idea its happening. Your phone thinks its connected to a normal tower.

In 2015, the Department of Justice issued guidelines requiring federal agents to obtain warrants before using Stingray devices in criminal investigations. This sounds like progress. But heres the catch:

• DOJ policy isnt law
• Theres no federal statute requiring Stingray warrants
• The policy covers federal agents but dosent bind state and local police working alone
• And the policy includes exceptions for “exigent circumstances” that investigators define broadly

The FBI has told local police to drop criminal cases rather then reveal Stingray use. Think about what that means. The surveillance technique is so secret, so protected, that the FBI would rather see criminals go free then explain in court how they tracked them. Court documents have revealed that FBI instructed local police departments to never disclose the use of cell site simulators, even if it meant dismissing charges.

In United States v. Lambis, a federal court ruled that using a Stingray constitutes a search requiring a warrant. The court suppressed evidence gathered from warrantless Stingray use. But this is one court decision – not a nationwide rule. Different courts reach different conclusions. Investigators in some jurisdictions face warrant requirements; investigators in others operate with fewer restrictions.

The Commercial Data Loophole That Makes Carpenter Meaningless

Heres the most disturbing development in federal phone surveillance: agencies have discovered they can simply buy the location data that Carpenter said requires a warrant.

The FBI, Department of Homeland Security, and Department of Defense have all been caught secretly purchasing cell phone location data from commercial data brokers. These companies collect location information through smartphone apps – weather apps, games, shopping apps, anything that requests location permission. They aggregate and sell this data to anyone willing to pay, including federal law enforcement.

The agencies argue that Carpenter dosent apply to purchased data. The Carpenter decision addressed information obtained from phone carriers through legal process. When investigators buy data on the commercial market, there not compelling anyone to produce anything – there just making a purchase. Its a distinction that completely undermines the Fourth Amendment protection Carpenter supposedly established.

Think about how this works in practice:

• An investigator wants your location history
• Under Carpenter, they need a warrant supported by probable cause
• Or they can just buy your location data from a broker, and suddenly no warrant is needed
• The protection exists only if investigators choose to request data through official channels
• If they choose the commercial route, the protection evaporates

Several members of Congress have introduced legislation to close this loophole. The Cell-Site Simulator Warrant Act would establish clear warrant requirements for both Stingray devices and purchased location data. So far, the legislation has died in committee. Federal agencies continue purchasing location data without warrants.

How Long Your Carrier Keeps Your Records

Understanding data retention periods helps you grasp how far back investigators can look into your life.

• AT&T retains call records, cell site information, and tower dump data for seven years
• T-Mobile keeps similar data for two years
• Verizon holds it for one year

If your an AT&T customer, federal investigators can potentially reconstruct your movements going back to 2018 as of today. Seven years of were you went, who you called, what towers your phone connected to – all sitting on AT&T servers, available with appropriate legal process.

The retention periods vary by carrier and by specific data type, but the bottom line is this: your phone has been generating a detailed record of your life, and that record exists on corporate servers regardless of wheather anyone has requested it yet.

Heres what this means for federal investigations. If your under investigation today, investigators can request your AT&T records and see were you were in 2019. They can identify patterns in your movements. They can place you at specific locations on specific dates years ago. They can corroborate or contradict your statements about past events using records that existed long before you knew you were a subject of investigation.

The data retention also means that investigations reaching back years can still access phone records. That business deal from five years ago thats now under scrutiny? If you were an AT&T customer, your location data from that period probly still exists. Your movements during the relevant time period are reconstructible.

The Metadata That Reveals Everything

Even when investigators cant get the content of your communications, the metadata tells them almost everything they need to know.

Metadata is data about data. For phone records, metadata includes:

• Who you called
• When you called them
• How long the call lasted
• Were you were when you made the call

It dosent include what you said – thats content, and content generaly requires a wiretap warrant. But the metadata alone is extraordinarily revealing.

Investigators can map your social network from call metadata. Everyone you talk to, how often you talk to them, when your conversations happen. They can identify your closest associates, your business contacts, your family relationships – all from the pattern of calls without ever hearing a single word.

Location metadata tells them everything about your life patterns:

• Were you sleep every night
• Were you work every day
• Were you go on weekends
• Who you visit and how long you stay
• The routes you drive and the places you stop
• Your entire physical existence reduced to data points

Courts have been slow to recognize how revealing metadata is. The traditional view was that metadata was less sensitive then content – just envelope information, not the letter inside. But modern metadata analysis can reveal more about your life then any individual communication ever could. The pattern is the point.

What You Can Actually Do About Phone Surveillance

If your already under federal investigation, your options for protecting phone data are limited. Destroying evidence is obstruction of justice. Switching carriers dosent eliminate historical records. Getting a new phone dosent erase what your old phone already transmitted.

But understanding the surveillance helps you understand your situation:

• If you know investigators likely have your location history, you know that any alibi you provide will be checked against tower records
• If you know they can map your social network from call data, you understand why investigators ask about people you might not think are relevant

Work with your attorney to understand what records exist and what investigators likely have. Your lawyer can file motions challenging the legal basis for data collection. If investigators used Stingrays without warrants, or obtained tower dumps without proper authorization, suppression motions might succeed.

For anyone not yet under investigation: understand that your phone is constantly generating a record that can be used against you. The convenience of modern technology comes with surveillance capabilities that previous generations never imagined. Every tower connection, every location ping, every call – all of it stored, all of it potentially accessible to federal investigators.

The Bottom Line On FBI Phone Tracking

The FBI can track your phone in multiple ways, with varying levels of legal protection:

• Basic subscriber information requires only a subpoena
• Historical location data requires a warrant after Carpenter – but investigators can bypass that requirement by purchasing commercial data
• Stingray devices require warrants under DOJ policy, but the policy isnt law and includes exceptions
• Tower dumps sweep up everyone’s information regardless of individual suspicion

By the time you know your under investigation, investigators may already have years of your phone records. Your carrier has been storing your location data this entire time. The investigation timeline and the data retention timeline run independently – investigators can reach back years into your life using records that accumulated long before you became a subject.

Your phone has been a witness against you from the day you activated it. Every cell tower it connected to, every location it pinged, every call it made – all recorded, all stored, all potentially available to federal investigators. The question isnt wheather they can track your phone. The question is how much of your life they’ve already reconstructed.