Maryland Code, Criminal Procedure § 2-305

(a) A member of a state, county, or municipal law enforcement unit of another state who enters this State in fresh pursuit and continues within this State in fresh pursuit of a person to arrest the person on the ground that the person is believed to have committed a felony in the other state has the same authority to arrest and hold the person in custody as has a member of a duly organized State, county, or municipal corporation law enforcement unit of this State to arrest and hold a person in custody on the ground that the person is believed to have committed a felony in this State.

(b) This section does not make unlawful an arrest in this State that would otherwise be lawful.