Blunt force trauma is what killed a man in Portland Police custody, according to the state medical examiner.

James Chasse

Officials say James Chasse died from a broad blow to the chest, and have ruled the death accidental. A toxicology report also came back negative, but examiners are still waiting for a blood alcohol test to come back.

According to Karen Gunson of the state medical examiner's office, it means that the trauma could have come from falling down, or having somone fall on him - and the blow was not likely from being kicked or punched.

The injury caused ribs to fracture, so Chasse could not breathe, Gunson said.

Police took Chasse into custody Sunday night after a confrontation in Northwest Portland. Officers said he was acting odd and may have been intoxicated.

Gunson added that Chasse was known to be mentally ill, and that probably would explain his behavior at the time.

Witnesses said they watched officers chase down and tackle the suspect for several minutes.

Jamie Marquez, courtesy the Portland Mercury

Medics and police check on a man who later died in police custody.

After police used a taser on Chasse, he later showed difficulty breathing, according to Detective Paul Dolbey.

Medics checked him out at the scene and said his vital signs were normal, according to investigators. He was taken to the Multnomah County Detention Center, and later showed more signs of breathing problems. Police say they were taking him to the hospital when he died.

Gunson said that from a medical examiner's point of view, the officers involved did not know Chasse would die based on their actions.

The officers involved in Chasse's custody were identified as Sgt. Kyle Nice, 39, a 14-year veteran of the Portland Police Bureau, officer Christopher Humphreys, 31, a seven-year veteran of the bureau and Dep. Brett Burton, 26, a two-year veteran with the Multnomah County Sheriff's Office.

A statement released Friday by the Portland Police Association said: "We understand the Medical Examiner has released a report today that comments on the manner and cause of death concerning James Chasse. While we understand the incident has garnered press coverage and community comment we remind everyone that there is an ongoing, thorough, and professsional investigation taking place. Next week there will likely be a review by the Multnomah County District Attorney's office. We are confident in our officers and believe they will be vindicated through the review process. We are unable to comment about the specifics of this case because the investigation is continuing, but following the review by the D.A. we will have a detailed response at that time."