The Ventura County Medical Examiner's Office has performed an autopsy on a 36year-old Simi Valley man who died after struggling with several police officers who were trying to arrest him.

But nearly a week after the death of Charles Anthony Torrence, Chief Medical Examiner Ronald O'Halloran said his staff is still "unsure" of how he died.

O'Halloran said he is waiting for toxicology results, which can take up to four months to be released.

"We're really not sure at this time," he said. "We need more information. (Toxicology results) could come back as soon as a month depending on what they find."

According to police reports, Torrence became "combative" when officers tried to detain him in front of his Parker Court home after his girlfriend called 911 around midnight July 17 to report a domestic violence incident.

When the first officer arrived at the 2200 block of North Parker Court, he observed a "violent confrontation" in the street.

Sgt. Adam Darough said the officer approached Torrence, who was fighting with a neighbor.

The officer, Darough said, was able to "verbally intervene and convince the suspect to cease his aggressive behavior."

But when the officer attempted to arrest Torrence, he became "resistive and confrontational" and fled, according to the report. After a short foot pursuit, the officer caught up with Torrence, who, according to police, started to resist again.

Additional officers arrived to assist and, according to reports, they attempted to restrain Torrence using "a number of tactics," which Darough said would include verbal commands and physical restraint.

One officer attempted to deploy a Taser, but police say it's unclear whether the Taser made contact.

Officers said Torrence continued to "violently resist" the arrest, but eventually they were able to handcuff him.

According to the report, Torrence began experiencing medical problems soon after the arrest. Paramedics took him to Simi Valley Hospital, where he was pronounced dead at 5:45 the next morning.

Three officers were also taken to local hospitals with minor injuries sustained during the struggle. They were treated and released several hours later.

Sgt. Darough said the officers don't know if the Taser stunned Torrence. "It was deployed, but we're still unsure of its effectiveness," he said.

O'Halloran said he didn't find marks on the body that would confirm the Taser made contact.

"There was no clear evidence on the skin," O'Halloran said.

In May 2007, Reymundo Garcia Guerrero died after SVPD officers used a Taser 11 times on the 33-year-old. The Ventura County District Attorney's Office cleared the officers, saying they were "fully justified" in the amount of force they used to subdue Guerrero.

Guerrero, who was high on cocaine, went into cardiac arrest shortly after being stunned when he refused to exit his vehicle. O'Halloran determined that Guerrero's death was most likely caused by asphyxia related to being restrained by police, but the D.A.'s office concluded that Guerrero's actions—not those of officers—are what ultimately led to his death.

A study funded by the U.S. Department of Justice between 2005 and 2007 revealed that 98 percent of those stunned by a Taser suffered no injuries. In a 2005 Army study, it was concluded that Tasers could cause ventricular fibrillation, the irregular heart rhythm characteristic of a heart attack. Amnesty International has documented nearly 250 deaths that have occurred after the use of a Taser.