Do the police really have to arrest someone if there is a domestic violence allegation? Based on the law, the police are never required to arrest anyone based on a mere allegation. In order to arrest a person, police must either have a warrant or probable cause to believe a domestic violence based crime has been committed (remember, domestic violence is not a crime, but rather a designation). These requirements are set forth Colorado Revised Statute 16-3-102. C.R.S. 16-3-102 provides that a peace officer may arrest a person when he has a warrant requiring his or her arrest, a crime has been or is being committed in his presence or he has probable cause to believe an offense was committed and has probable cause to believe that offense was committed by the person to be arrested. Probable cause requires more than a mere allegation.
It is, however, true that if a police officer has probable cause to believe a domestic violence based crime has been committed, the officer must arrest the person he has probable cause to believe committed that crime. C.R.S. 18-6-803.6 provides as follows: When a peace officer determines that there is probable cause to believe that a crime or offense involving domestic violence has been committed, the officer shall, without undue delay, arrest the person. Importantly, this statute also tells police that they are not required to arrest anyone if there is no probable cause.
Despite what the law says, in a vast majority of instances, if police are called out on a report of a domestic violence incident, at least one person is likely going to be arrested. This is true even if the people involved in the domestic dispute did not call the police. For example, a neighbor may call the police and neither of the parties actually involved in the incident want police involvement. The police will still likely arrest at least one of the parties involved.
Under certain circumstances, the police may even arrest both parties involved. This is not very common, but does happen on occasion. By law, this should only happen if police believe both parties involved committed a crime involving domestic violence. In reality, this usually happens when the police are uncertain as to exactly what happened. By arresting both parties, it is left up to the prosecuting attorney to attempt to figure out what happened and decide whether to dismiss the case against one person and pursue the case against the other person or to dismiss the charges against both people. In rare situations, the prosecution may be able to proceed with charges against both parties, but this is unusual because often there are no witnesses to the incident other than the two parties arrested. Because each person charged has the right to remain silent under the 5th Amendment, without 3rd party witnesses, the prosecution cannot move forward with charges against either party.