File photo of Lei Yang, who died on May 7 about an hour after he was detained on suspicion of soliciting prostitution. [Photo from the web]

An autopsy report released by Beijing's top prosecuting authority on Thursday showed that Lei Yang, who died after being taken into police custody in early May, choked on his own vomit.

Beijing People's Procuratorate said the autopsy result had been reviewed by a group of experts from across the country.

It also confirmed that two officers from Dongxiaokou police station in the capital's Changping district had acted improperly and their arrest for negligence had been approved.

The officers, identified as the station's deputy director surnamed Xing and an auxiliary police officer surnamed Zhou, allegedly interfered with investigations following Lei's death, the procuratorate said.

Lei, 29, died on May 7 about an hour after he was detained on suspicion of soliciting prostitution.

Police statements said Lei was stopped outside a foot massage salon at 9:14 pm that day, but refused to cooperate with officers and was handcuffed after attempting to escape.

He was taken to hospital at 10:05 pm after appearing to be unwell in the police car and was pronounced dead at 10:55 pm, the statements said.

Lei's family disagreed with the statements, believing that the police officers involved had acted improperly. Through a lawyer, they requested that prosecutors investigate and asked for a third-party independent autopsy.

In June, prosecutors accepted the request and opened an investigation into the case.