By J.D. Miles & Jack Fink,

DALLAS (CBSDFW.COM) – Questions surrounding the case of a Dallas County Jail inmate who escaped from Parkland Hospital Tuesday night appear to be answered by sources close to the investigation.

CBS 11 has learned Franklin Davis, the man accused of killing 16-year-old Shania Gray earlier this year, had been removed from his arm and leg shackles Tuesday night before taking a deputy’s gun and leading police on a manhunt through Dallas’ medical district.

Sheriff Lupe Valdez admitted during a press conference Wednesday that mistakes were made, but how and why Davis was even at Parkland has now become part of the investigation.

Valdez admits not all procedures were followed properly.

Davis is facing the death penalty after admitting on-camera in August that he killed Gray, a Carrollton high school student.

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Sheriff Valdez says Davis was brought to Parkland Saturday after making ‘severe’ complaints, but didn’t specify the illness, citing privacy laws.

Davis was in the process of being released from Parkland Tuesday when he surprised the deputy.  “There was a struggle, he was over-powered.”

Valdez refused to name the deputy who was overpowered. But CBS 11 News has learned from sources that  the unnamed deputy removed Davis’s arm and leg restraints so he could shower before returning to jail.

Sources also say the one deputy on guard was inexperienced and that his gun belt was not standard issue and broke allowing Davis to grab his gun following a brief struggle that left the officer injured. “If there was a mistake, I think he’s having a bigger struggle with that than his injury,” said Valdez.

Davis should have been considered dangerous to authorities.  He’s facing the death penalty.

Authorities found Davis inside a van in a parking lot near the hospital a few hours after his escape.  And now, he’s back in jail.

But CBS 11 has learned Davis had been in and out of Parkland several times since his arrest, and some deputies say they believe Davis may have been ‘casing’ the hospital during those previous visits.

Just this week, the county broke ground on a $40 million medical facility at the jail.  When it opens in 2014, inmates will be treated at the jail instead of having to be transported to Parkland.

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