Black Maria

a police van used for the conveyance of prisoners. It is suggested that the name is derived from that of Maria Lee, a black woman in Boston in the early 1800s who kept a lodging house for sailors, but cooperated with the police in the arrest of any lodger who became unruly or violated the law. she was of such great size that when the police required help they sent for Black Maria, who soon collared the refractory men and led them to the lockup.