NOTTINGHAM, England (NEXSTAR) – A U.K. man known for dressing as Batman villain the Joker has been found guilty after dropping a bowling ball from his apartment window onto a worker’s head during a dispute one year ago, police say.

Damien Hammond, 31, was convicted Friday of grievous bodily harm in the Dec. 2019 incident, which started when the laborers started clearing a television from the sidewalk of Hammond’s Nottingham building.

Police in Nottingham, located about 130 miles north of London, said Hammond shouted at the men that the TV was his and he would come down, then hurled the bowling ball, encased in fabric from a pair of black jeans, out of the window.

The ball struck the victim in the head, knocking him to the ground and opening a large gash that left his face covered in blood, police said. He was taken to the hospital where doctors diagnosed him with a fractured skull and brain trauma.

The victim has not fully recovered from his injuries and was told he may experience seizures and blackouts for the rest of his life, the Nottingham Post reports.

Hammond said in court that he had been taking a synthetic drug called “Mamba” for three days leading up to the incident and believed the men were “coming up to kill me off,” according to the paper.

Hammond has a reputation in Nottingham for walking around dressed as the Joker in what police think is an attempt to “induce fear into members of the public and retail staff,” according to the BBC.

He will be sentenced January 29.