The July 11 death of Francis Gigliotti was deemed to be a matter of homicide in the medical examiner's findings provided to Essex County District Attorney Paul F. Tucker office Thursday, the Salem-based prosecutor said in a statement. Tucker's office is investigating "whether the actions of the police officers were justified," according to the statement. Seven officers in Haverhill, north of Boston near the New Hampshire line, were put on paid leave after the handcuffed man became unresponsive and died as he was restrained in a prone position.