What Happens When Someone Is Detained?
A detainment means a person is briefly held on “reasonable suspicion” of criminal conduct or that someone is armed. According to the Legal Information Institute at Cornell Law School, reasonable suspicion means there are “specific, articulable facts that would lead a reasonable officer to believe that criminal activity is occurring.”
When somebody is initially pulled over at a traffic stop or stopped and frisked in the street, for example, they’re usually being detained. Many investigative detainments, or temporary restrictions of someone’s liberty, last only a few minutes while officers confirm or dispel their suspicions.
“Every situation that a police officer encounters on a daily basis is different,” Arkansas State Police Sgt. Scott O. Russell wrote in a paper for the University of Arkansas System's Criminal Justice Institute in 2016. “Therefore we have no ‘bright line’ or clear cut law that defines when a person can or cannot be detained for every situation that you may find yourself in.”
If a person stopped by police is free to leave, the interaction is considered a consensual encounter, not a detainment.
What Happens When Someone Is Arrested?
If a detainment happens in a public place and police develop “probable cause” that a person committed a crime—for example, learning the vehicle they’re driving was stolen—they can legally proceed with an arrest. Compared with reasonable suspicion, the probable cause standard requires a higher degree of certainty that criminal conduct is occurring or has occurred.
In May 1983, California Highway Patrol officers pulled over serial killer Randy Kraft at a routine traffic stop on suspicion of drunk driving. Kraft failed a sobriety test and was arrested at the scene. Then police noticed a corpse in the front passenger seat of Kraft’s vehicle, giving officers immediate probable cause to conduct a more thorough search of the car, where they also discovered what’s believed to be a list of Kraft’s victims.
In 1989, Kraft was convicted on 16 counts of murder and sentenced to death.
By comparison, police usually cannot arrest someone in a private home without a court-issued warrant, which is granted once investigators provide sufficient evidence of criminal conduct. In other cases, direct police observation of criminal activity—for example, watching somebody break into a car or burglarize a home—is by itself sufficient grounds for arrest.
An arrested person first learns about the charges they face in a process called arraignment. In the federal criminal process, suspects appear before a judge the same day as their arrest or the next day. State laws vary when it comes to how long people can be held in local jails before their arraignment. Some set specific time limits—usually between 24 and 72 hours—while others require that arraignments begin “without unnecessary delay.”
While awaiting trial, suspects may be held in local jails or federal detention centers, or released on bond or under court-ordered conditions, such as travel restrictions or electronic monitoring.
Constitutional Rights During an Arrest Versus Detainment
When somebody is arrested or in custody (detained) for interrogation, police are required under the Fifth Amendment to read the suspect their Miranda rights. These constitutional protections grant them the right to remain silent and to an attorney, and they state that anything they say “can and will” be used against them in court.
Miranda rights are not automatically triggered during traffic stops and other forms of detainment that don’t involve interrogations. In these situations, a person cannot be arrested solely for remaining silent, even if it raises suspicions, and police also aren’t required by law to stop asking questions just because someone asks for a lawyer.
Under some state laws, a detained person must identify themselves to varying degrees if stopped by police. Failure to comply can qualify as a misdemeanor or petty offense.
