Malaysian authorities said they were investigating after a man’s wife accused police officers of torturing her husband before beating him to death.

Police have opened a murder inquiry after a postmortem on N Dhamendran revealed “criminal elements” and said they were questioning four officers who were allegedly involved.

Dhamendran died in custody on May 21, more than a week after he was arrested over a fight, AFP reports.

The postmortem showed 52 injury marks on his body, including extensive bruising and wounds likely made by a cane and stapler, according to Dhamendran’s wife, M Marry.

Marry called on authorities to swiftly bring to justice those responsible for her husband’s murder, which carries the mandatory death penalty upon conviction.

His lawyer said he had staple wounds in his ears and “not one inch” of his body was spared from beating. “This is obviously a form of torture by the police… There is adequate evidence to bring murder charges against all police personnel involved,” N Surendran told AFP.

Allegations of police brutality in Malaysia are commonplace, but prosecutions have been few. According to the home ministry, a total 0f 156 detainees died in custody from 2000 to 2011.

Home Minister Zahid Hamidi said interrogation procedures would be reviewed to ensure that no similar deaths occur in the future. “Those responsible are individuals, not the entire force,” he added.