A time-critical investigation into the death of a British man whose body was found in a ransacked property on the Caribbean island of Grenada has stalled because of diplomatic delays between the two countries.

Charity workers supporting the family of Andrew Frederick are demanding immediate government intervention to clear the path for a full investigation to begin almost 10 months after his death, which has been ruled a homicide by a pathologist.

The Murdered Abroad charity has called on the foreign affairs select committee to step in after Grenadian police found there was “no basis … that any homicide has occurred” and closed the case.

This was despite a report from an autopsy, done in the week he died, saying Frederick, 47, had suffered “blunt force trauma”, was tortured, including by removal of his toenail, and ruling the death a homicide.

Frederick’s body was found on 4 January.…