Beijing prosecutors announced Sunday that the choice of a forensic center to perform an autopsy on a man whose mysterious death raised suspicions of police brutality is lawful.

On Saturday afternoon, Qian Lieyang, a lawyer representing a police officer surnamed Xing - one of five officers involved in the death of 29-year-old Beijing resident Lei Yang, who died of an alleged heart attack in police custody in Beijing's Changping district in May - said the appointment of Beijing Mingzheng Forensic Identification Center violates the Criminal Procedure Law and suggested that Beijing's procuratorate switch the forensic identification center used in the case, the Legal Daily reported.

Qian wrote a legal opinion to the Fourth Branch of the People's Procuratorate of Beijing Municipality, saying Lei Yang's family selected the forensic center for the autopsy and that Lei's family and an expert they commissioned were present during the procedure, which violates the Criminal Procedure Law.

The procuratorate said on its official Sina Weibo account that it has heard reports from lawyers on both sides and has determined that entrusting the autopsy to the lab was lawful, adding that prosecutors had supervised the autopsy from beginning to end and will handle the case objectively, safeguarding the rights of the accused.

Chen Youxi, the lawyer representing Lei's family, denied Qian's accusation.

"The selection of the forensic identification center is completely legal. The accusations are just the tactics of the [officers' lawyers] to delay the release of the autopsy report," Chen told the Global Times.

Chen said the investigators picked three forensic centers registered at the procuratorate, and Lei's family and lawyer selected one of them. The family did not know anyone from the center, and the center has no interest in the case, he stated.

Chen said he will look into whether the autopsy procedure and results are problematic once he receives the autopsy report. Chen also urged investigators to release the report soon. "It's been over a month since the autopsy, and a conclusion should have been made long ago," he said.

Lei Yang's death while he was detained during a raid on a foot massage parlor triggered a public outcry and raised suspicions of police brutality and abuse of official power. Police claim Lei suddenly fell ill and died after he resisted arrest and attempted to escape.

Prosecutors in Beijing said on June 1 that the five police officers involved in Lei's detainment were under investigation.