Police Slang & Codes
this ten-code is universally used by law enforcement officers to signify "Acknowledgment" or "OK."
What is 10-4?
This unique biological pattern left behind by friction ridges on fingers is the oldest form of biometric identification
What is a fingerprint?
Officers must read these warnings to a suspect before conducting a custodial interrogation.
What are Miranda rights?
Often used as a general alert or radio check, this is the most common ten-code meaning "Receiving well" or "O.K."
What is 10-4?
Named after a landmark 1966 Supreme Court case, these warnings must be read to a suspect prior to a custodial interrogation.
What are Miranda rights?
In police slang, this heavy vehicle is often used by SWAT teams to safely breach barricaded buildings.
What is a BearCat (or APC)?
This chemical spray glows blue under ultraviolet light when it comes into contact with even trace amounts of blood.
What is Luminol?
This Constitutional Amendment protects citizens against unreasonable searches and seizures.
What is the Fourth Amendment?
If an officer asks dispatch for your "10-20," they are requesting this critical piece of information.
What is your location?
This Constitutional Amendment protects citizens against unreasonable searches and seizures.
What is the Fourth Amendment?
This three-letter acronym refers to the database used nationwide to share criminal history and look up stolen property.
What is NCIC (National Crime Information Center)?
This is the term for the study of insects and their life cycles to determine the post-mortem interval of a body.
What is forensic entomology?
This legal standard requires more than a mere hunch and allows an officer to briefly detain and frisk a person for weapons.
What is reasonable suspicion?
This ten-code is broadcast immediately when an officer is in urgent danger and requires immediate emergency assistance.
What is 10-99? (Note: Regional variants exist, such as 10-33 or 10-78).
To obtain a search or arrest warrant, an officer must demonstrate this legal standard—not just a hunch—to a judge.
What is probable cause?
When an officer radios that they are "Code 4," it means this has been established at the scene.
What is safety (or the situation is under control)?
This system, managed by the FBI, blends forensic science and computer technology to match DNA profiles across the country.
What is CODIS?
This legal rule prevents evidence collected in violation of a suspect's constitutional rights from being used in a trial.
What is the exclusionary rule?
In California's penal code system, this three-digit number is widely recognized as the code for a disturbance of the peace.
What is a 415?
This legal rule dictates that evidence obtained through an illegal search or seizure cannot be used against a defendant at trial.
What is the exclusionary rule?
This slang term refers to a rookie officer who is still undergoing field training with a veteran partner.
What is a boot?
This forensic discipline analyzes the markings, scratches, and grooves left on a bullet after it is fired from a weapon.
What is ballistics (or toolmark identification)?
This standard of proof is required for a police officer to obtain a search or arrest warrant from a judge.
What is probable cause?
When a unit goes "10-7," it means they are out of service; this code means they have arrived back on duty and are "in service."
What is 10-8?
This specific, localized type of warrant allows police officers to enter a premises without knocking or announcing their presence if safety or evidence is at risk.
What is a no-knock warrant?