PHOENIX – A Maricopa County Sheriff’s Office detention officer died Wednesday evening one day after being physically attacked by an inmate at a Phoenix jail, authorities said.

The Lower Buckeye Jail inmate, Daniel Davitt, grabbed Officer Gene Lee by the throat without warning and kicked Lee’s feet out from under him, Sheriff Paul Penzone said during an afternoon press conference.

Lee landed headfirst on the concrete and lost consciousness, Penzone said.

Lee immediately received medical treatment and was transported to Banner University Medical Center in Phoenix.

Dr. Paul Dabrowski said Wednesday that Lee, who was in a coma, was in very critical condition with a brain injury and his prognosis was “very poor.”

Dabrowski said a procedure was done to remove blood and pressure from around Lee’s brain.

Penzone said Davitt, 59, had been in MCSO custody for two years pending charges for sex crimes involving children. He was in the process of being transferred to the Pinal County jail system after the attack.

Penzone said he will do everything he can to ensure that Davitt is convicted and “sees the longest sentence practical” for the attack on Lee.

Lee was a six-year veteran of MCSO who was a member of the posse before becoming a full-time employee, Penzone said.

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