UPDATED | August 25, 2016 9:30 PM

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DALLAS (CBSDFW.COM) – A Dallas County Jail inmate is back in custody this afternoon after he was released by mistake.

Tony Lee Cason, 56, is accused of killing his psychiatrist, Dr. Ruth Ann MarDock at Timberlawn Mental Health System this summer.

The Dallas County Sheriff Lupe Valdez told CBS11, “All we can say right now is that it was an error and its going to lead us where the buck stops.”

Sheriff Valdez said it’s not clear yet if it was as human error or a system error.  She said if it was a human error, someone will be held accountable.

“If it was a human error than we are going to have to double check if it was communications error if we need to talk to each other better a print or something error than we need to handle that,” said Valdez. “But yet a mistake was made we aren’t sure exactly what it was.”

MarDock was treating Cason at Timberlawn for suicidal tendencies. She decided to have him transferred to another psychiatric facility in June, according to an arrest affidavit.

Cason was enraged when he found out about the transfer and tackled MarDock as she turned a corner into his room. He then slammed her head against the linoleum floor, the affidavit says. She died of severe brain trauma two days later.

Cason was on the loose for almost a week after his accidental release last Friday.

Cason was charged with manslaughter in the beating death of MarDock.

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