PONDER (CBSDFW.COM) – The man responsible for shooting his own children, and his ex-wife’s boyfriend in Ponder, let his ex-wife live on purpose, according to investigators who are close to finishing their investigation.

Justin Painter used a .45 caliber semi-automatic handgun in the murders, according to Ponder Police Chief Robert Genova. Painter had owned the gun for some time, Genova said, and it may have been a gift.

aponderkids Shooter Who Murdered His Children, Let Ex Wife Live On Purpose

Amanda Simpson’s children (Facebook)

Investigators said Painter was dropping his children off at the home where his ex-wife lived in Ponder, the morning of May 16. After putting the children in the living room, investigators believe Painter went into the bedroom and killed 29-year-old Seth Richardson. Then he went back to the living room and shot the three children, Caydence, Drake and Odin. All three were shot multiple times.

On a 911 call released by Denton County Friday, Amanda Simpson tells the operator she had just gotten out of the shower and was in her bedroom when the shooting happened. She didn’t realize until several minutes into the call, that she had also been shot in the back. She told the operator her ex-husband said he was going to shoot himself, so she would have to live with it.