By Brian Maass

DENVER (CBS4)– CBS4 has learned an inmate from the Denver City jail is hospitalized in critical condition after getting into a physical altercation with multiple Denver Sheriff Department deputies Wednesday night. He has been transferred to Denver Health Medical Center.

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Simon Crittle, a spokesman for the Denver Sheriff Department, confirmed only that “An incident occurred at the Downtown jail on Wednesday evening. The facts and circumstances surrounding the incident are being reviewed. To protect the integrity of the investigation, we are unable to release any additional information at this time.”

Michael Marshall (credit: Denver Sheriff)

Michael Marshall (credit: Denver Sheriff)

Crittle declined to release any other details.

Multiple law enforcement sources told CBS4 investigator Brian Maass that the 50-year-old inmate, Michael Marshall, was acting erratically, was uncooperative, and tried to flee when approached by a deputy on the fourth floor of the downtown detention center.

Ultimately, sources say several Denver Sheriff deputies went “hands on” with Marshall, using force in an attempt to restrain him. Court records show Marshall is 5-foot-8 and weighs 130 pounds. Sources say the inmate continued to resist and struggle and at one point he was placed in a restraint chair.

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He was handcuffed but deputies said he continued to struggle, and at some point, he stopped breathing. Deputies performed CPR on Marshall before he was transferred to the hospital.

(credit: CBS)

(credit: CBS)

Although officials refused to release details about what happened, CBS4 learned Marshall was in jail on a minor trespassing charge. Records show he was arrested in Denver Nov. 7 for trespassing. Marshall has a lengthy arrest record dating back to 1993 in Denver according to state records. He has numerous drug arrests and Colorado Bureau of Investigation records show Marshall has served time in state prison.

Sources say deputies were still being interviewed about the incident Thursday night. New Denver Sheriff Patrick Firman was informed of the incident and was at the downtown detention center Wednesday night.

This story will be updated as more information becomes available.

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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.