By Brian Maass

DENVER (CBS4)– Denver District Attorney Mitch Morrissey ruled Thursday there would be no criminal charges against six Denver Sheriff’s deputies in relation to the death of inmate Michael Marshall last November.

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“The force that we saw was not unreasonable in light of the situation the sheriffs were in,” said Morrissey.

Michael Marshall (credit: Denver Sheriff)

Michael Marshall (credit: Denver Sheriff)

Marshall, who had been jailed on minor charges, had been arrested Nov. 7. He suffered from mental illness. On Nov. 11, Morrissey’s report noted that Marshall began acting in a strange and erratic manner. When deputies saw him approach another inmate aggressively, they intervened.

Video of the incident was also released Thursday and Morrissey said he and one of his prosecutors had reviewed the jail video at least 100 times.

He said what struck him about the video was “the lack of aggressive behavior on the part of these sheriffs” who Morrissey noted did not hit, taze or use excessive force on Marshall.

(credit: Denver Sheriff's Dept.)

(credit: Denver Sheriff)

Deputies said they had to restrain Marshall when he wouldn’t obey instructions and resisted their directions. Although the prisoner would eventually stop breathing following the hands-on altercation with the deputies, Morrissey told CBS4 he thinks it’s likely that Marshall began suffering a heart attack before most of the physical interaction occurred.

The prosecutor said he thought “there is a good argument to be made,” based on the videotape, that Marshall began having a heart attack early in the encounter and before deputies handcuffed him and tried to restrain him.

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CBS4 Investigator Brian Maass interviews Denver District Attorney Mitch Morrissey (credit: CBS)

CBS4 Investigator Brian Maass interviews Denver District Attorney Mitch Morrissey (credit: CBS)

Darold Killmer, an attorney representing Marshall’s family, said “We’ve seen some of the video that was provided to us and I’m angry. I’m very angry at what I saw. It’s hard to imagine a more inappropriate overzealous response by law enforcement officials.”

Morrissey disagreed, “Everyone did what they could to restrain this man and they restrained him in a reasonable manner. I don’t believe they have any responsibility criminally for what occurred in the jail that day.”

Marshall was hospitalized after the incident and died nine days later.

Darold Kilmer, attorney for Michael Marshall's family (credit: CBS)

Darold Kilmer, attorney for Michael Marshall’s family (credit: CBS)

Morrissey said he knew his decision would be unpopular with some activists but “I’m not going to charge anyone for a crime beyond a reasonable doubt. They’ll be protesting in front of my house.”

He noted in his report that one of the sheriff’s deputies, Bret Garegnani, spent nearly 20 minutes performing CPR on the stricken inmate.

Bret Garegnani (credit: CBS)

Bret Garegnani (credit: CBS)

Don Sisson, an attorney representing five of the six deputies, said “The clients are relieved with the DA’s decision to not pursue criminal charges.”

Michael Marshall (credit: Marshall family)

Michael Marshall (credit: Marshall family)

Sisson said the deputies were glad the videotape was being released “so the public can see for themselves there is absolutely no excessive force and Deputy Garegnani engaged in extraordinary life saving measures.”

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CBS4 Investigator Brian Maass has been with the station more than 30 years uncovering waste, fraud and corruption. Follow him on Twitter @Briancbs4.