How police track criminals

Описание: Tracking criminals is a multi-stage process that blends traditional investigative techniques with increasingly sophisticated technology. Here’s a breakdown of how police track criminals, from the crime scene to apprehension.

Phase 1: The Crime Scene & Initial Evidence

This is the foundational step. Without good evidence, tracking is difficult.

· Physical Evidence: Fingerprints, DNA (blood, hair, skin cells), footprints, tire marks, and discarded items. These can identify a suspect directly through databases.
· Digital Evidence: Shell casings, weapons, tools, and unique materials can link a suspect to a scene or method of operation (MO).
· Witness Statements & Descriptions: Provides a physical description, vehicle details, direction of flight, or even a name.

Phase 2: The Investigative Phase - Building Leads

Detectives use the evidence to generate "leads."

1. Database Checks:
· Fingerprint Databases (IAFIS/NGI in the US): Run prints from the scene to find a match.
· DNA Databases (CODIS in the US): Match crime scene DNA to known offenders or other crime scenes.
· Ballistics Databases (NIBIN): Match shell casings to specific firearms used in other crimes.
2. CCTV & Video Footage: A cornerstone of modern policing. Police collect footage from:
· Public cameras (traffic, city centers, businesses)
· Private cameras (homes, Ring doorbells, banks, gas stations)
· Automated License Plate Readers (ALPR): Can track a vehicle's movement across a city or region.
3. Digital & Cyber Forensics: Perhaps the most powerful modern tool.
· Cell Phone Tracking: Police can obtain records from carriers showing a suspect's approximate location (cell tower pings), call logs, and contacts. They can also extract a vast amount of data from a seized phone.
· Social Media & Internet Activity: Criminals often brag, plan, or associate online. Profiles can reveal location, contacts, motives, and even real-time check-ins.
· ISP Records & Digital Warrants: Can link an IP address to a specific location or individual for online crimes.
4. Informants & Intelligence: Cultivating human sources within criminal networks for tips on who committed a crime or where they are hiding.
5. Public Appeals: Releasing CCTV images, sketches, or vehicle descriptions to the media and public can generate crucial tips.

Phase 3: Locating & Apprehending the Fleeing Suspect

Once a suspect is identified but location is unknown:

· BOLO/APB ("Be On the Lookout"/"All Points Bulletin"): Alerts all officers in the region to the suspect and their vehicle.
· Tracking Warrants: Police can obtain warrants for real-time tracking:
· Cell Phone Ping Tracking: Getting real-time location data from carriers.
· GPS Trackers: Covertly placing a tracking device on a vehicle (requires a warrant in most jurisdictions).
· Surveillance: Physical and electronic surveillance by specialized units to monitor associates and patterns.
· Fugitive Task Forces: Combine local, state, and federal (like U.S. Marshals) resources to hunt for serious offenders.

Phase 4: Specialized & High-Tech Tools

· Facial Recognition: Used cautiously to compare CCTV images against driver's license or mugshot databases. It's a lead generator, not standalone evidence.
· Genetic Genealogy: For unidentified DNA, investigators use public genealogy databases (like GEDmatch) to find relatives and build a family tree to identify a suspect (famously used in the Golden State Killer case).
· Drone Surveillance: For searching large areas, monitoring a location from above, or in hostage situations.
· Stingray Devices: Mimic cell phone towers to locate a specific phone's precise location. Their use is highly regulated.

Important Legal & Ethical Constraints

Police powers are not unlimited. Key concepts include:

· Probable Cause: Needed for arrests and most search warrants.
· Search Warrants: Required to search private property, seize phones/computers, or obtain detailed digital records. The "third-party doctrine" means data held by companies (cell carriers, social media) often requires a subpoena or warrant.
· Chain of Custody: Evidence must be meticulously documented to be admissible in court.

The Modern Tracking Ecosystem: A Summary

Modern criminal tracking is less about a single "silver bullet" and more about correlation. An investigation might:

1. Get a partial license plate from CCTV.
2. Use ALPR data to find the full plate and owner's address.
3. Check that owner's criminal record and find a DNA profile on file.
4. Match that DNA to evidence from the crime scene.
5. Obtain a warrant for the suspect's cell phone records, showing they were at the scene at the time of the crime.
6. Use real-time pings to locate and arrest the suspect.

The process is a constant interplay between old-school detective work (interviews, canvassing), forensic science, and digital surveillance, all bound by the legal framework designed to protect civil liberties.