under arrest
In police custody, as after committing a crime. The policeman stated that the criminal was under arrest and then handcuffed him.
*under arrest
arrested and in the custody of the police in preparation for the filing of a charge. (*Typically: be ~; put someone ~.) Stop where you are! You are under arrest! Am I under arrest, officer? What did I do?
under arrest
In police custody, as in They put him under arrest and charged him with stealing a car. [Late 1300s]