The family of a Massachusetts man who died in police custody after he was stopped at a sobriety checkpoint has filed a federal lawsuit claiming police beat him to death.

Kenneth Howe's family filed the lawsuit Tuesday. It names more than 30 state and local officers and says Howe was beaten to death.

The family's attorney cited a state medical examiner's finding that Howe's death was a homicide.

Authorities say the 45-year-old Worcester man was arrested after striking a trooper and trying to flee the North Andover checkpoint on Nov. 25. They say he became unresponsive while being booked and died at a hospital.

An attorney for North Andover officers called the lawsuit's claims "irresponsible."