Authorities have announced the cause of death in a case that has stirred a public outcry and issued arrest warrants for two police officers suspected of negligence.

An independent autopsy found that Lei Yang, 29, apparently choked to death on his vomit shortly after being taken into police custody, the Beijing People's Procuratorate said in a statement on Thursday.

The prosecutors also said arrest warrants had been issued for two officers from Dongxiaokou police station in Changping district on suspicion of negligence and misconduct, saying they acted improperly during Lei's arrest.

The officers, identified as the station's deputy director, surnamed Xing, and an auxiliary officer surnamed Zhou, are also accused of interfering with the investigation into Lei's death.

The findings come almost two months after Lei died about an hour after being detained on suspicion of soliciting prostitution.

According to police statements, Lei was stopped outside a foot massage salon at 9:14 pm on May 7. He refused to cooperate with the officers and was handcuffed after attempting to escape.

At 10:05 pm, he was taken to a hospital after appearing to be unwell in a police car, and he was pronounced dead at 10:55 pm.

Police said earlier that Lei died of a heart attack.

His wife, who did not wish to be named, challenged those statements and suspected police of wrongdoing. She asked that prosecutors investigate the officers' version of events and requested a third-party autopsy on her husband.

Lei's case has attracted huge public attention. A search for "Lei Yang" on Baidu, China's search engine, on Thursday generated 7.9 million results.

Chen Youxi, the family's lawyer, praised prosecutors' work, saying the family's main question in the case, the cause of death, had been answered.

"Lei was simply walking down the street when he was stopped by the police officers. He had not been drinking alcohol. That he choked on his own vomit could have happened if he had undergone external attacks," Chen said.

However, he also called for more detailed information and continued further investigation into the case.

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