ALEDO (CBSDFW.COM) – Despite a chilling confession to a 911 operator in which Jake Evans admits to killing his mother and sister, investigators are still no closer to finding a motive.

In the call shortly after the killing Evans is heard telling a 911 operator:
Evans: “I just killed my mom and my sister.‬”

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Police say Evans had shot his mother, Jami Evans, 48, and younger sister, Mallory Evans, in the home they shared in the town of Annetta South, a few miles south of Aledo.

Evans stayed on the phone with the 911 operator until police arrived and surrendered peacefully.

His father was out of town at the time but returned upon hearing the grisly news. Investigators are still have no idea what his motive was.

‪”Whatever the deal is, I mean, we don’t have an answer.  That’s the frustrating part of this. The family doesn’t have an answer,” said Larry Fowler, the Parker County Sheriff.

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Evans remains in jail without bond. He is not under suicide watch, but is under very close supervision, said Fowler. Evans has been quiet while locked up and has had no visitors.

“At this point he’s indicated he doesn’t want to meet with anybody, including family,” Fowler said.

Investigators said the teen had no problems with drugs or alcohol and had no history of violence.

“But clearly to me he’s been troubled about something, several somethings, I think, but do I know what that is at this point? No,” Fowler said.

‪Evans and his younger sister, Mallory, had been home schooled by their mother since January. Before that, Evans attended Aledo High School.

“He was quiet, real nice, real humble person, never really talked,” former classmate Aaron Vidrine. “I’m sad for him. I’m confused mainly, like why he did it‬.”

Family members declined to talk on camera. Family told CBS 11 Jami Evans was a well respected teacher and former vice principal and an upstanding citizen in the community.

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A prayer service was held at First Baptist Church for anyone mourning.

The murders shocked the small town of Aledo and neighboring Annetta South community. Investigators say even though the suspect surrendered, they may never know what Evan’s motive was.