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The sister of the Iraq war veteran accused of killing a former Navy SEAL sniper and his friend last weekend at a Texas shooting range told authorities her brother confessed to the murders but was not sure if he was on drugs at the time of his confession, MyFoxDFW.com reported.

"Listen, my brother just came by here. I live at... He's now left. He told me he's committed a murder and I'm terrified for my life," Laura Blevins, the sister of Eddie Ray Routh, said in the 911 call. Routh has been charged in the killing former SEAL Chris Kyle and his friend Chad Littlefield.

She told the operator that Routh is "psychotic" and she's afraid he will return to her house.

"I don't know if he's being honest with me," Blevins says, referring to his confession. "I don't know if he's on drugs or not."

Her husband told the operator that Routh was released from a mental hospital about a week ago and that he had been "acting a little weird."

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According to an arrest warrant affidavit, Routh told his sister he "traded his soul for a new truck," referring to the truck he allegedly stole from Kyle after the shooting.

Routh's brother-in-law also told the 911 operator that Routh was recently diagnosed with post-traumatic stress disorder. The brother-in-law's name could not be heard on the recording, though part of it was unintelligible.

On Tuesday, Routh remained in his jail cell instead of meeting with his court-appointed attorney or relatives, Erath County Sheriff Tommy Bryant said in a telephone interview. Routh had demanded a cigarette in exchange for a meeting, but smoking isn't allowed in the jail, Bryant said.

The sheriff said he doesn't know which relatives came to visit Routh in the jail in Stephenville, about 75 miles southwest of Fort Worth.

Routh was taken to a mental hospital twice since last fall and told authorities he suffers from PTSD, according to police records.

Routh, a member of the Marines Corps Reserve, threatened to kill his family and himself Sept. 2, according to police records in Lancaster, where Routh lives. Police then took Routh to Green Oaks Hospital for psychiatric care. Dallas police records show Routh was taken to the same mental hospital in mid-January after a woman called police and said she feared for Routh's safety.

Green Oaks will not release patient information, citing privacy laws.

Kyle and Littlefield apparently had been helping Routh work through PTSD, said Travis Cox, director of FITCO Cares, the nonprofit that Kyle set up to give in-home fitness equipment to physically and emotionally wounded veterans.

Kyle, 38, left the Navy in 2009 after four tours of duty in Iraq, where he earned a reputation as one of the military's most lethal snipers. He authored his memoir, "American Sniper," which became a best seller. Littlefield, 35, was Kyle's friend, neighbor and "workout buddy," and also volunteered his time to work with veterans, Cox said.

Routh joined the Marines in 2006 and rose to the rank of corporal in 2010. His military specialty was small-arms technician, commonly known as an armorer. He had been stationed at Camp Lejeune, N.C., and served in Iraq from 2007-08 and in the Haiti disaster relief mission in 2010. Prior to his arrest, he was in the individual ready reserve.

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The Associated Press contributed to this report