A Kansas father has been charged with murder after his 3-year-old daughter picked up his loaded, unsecured handgun and shot her 1-year-old sister fatally in the head.

Michael Tejeda, 24, was also charged with felon in possession of a firearm and two counts of aggravated child endangerment.

According to KAKE, Tejeda told investigators the children’s mother was away and he was purportedly watching the children, but he fell asleep and awoke about 6 p.m. At that point, he said, he realized the gun he was legally barred from having was still in a fake holster in his wasteband — where it could easily fall out — so he took it out himself and put it on the fireplace, which he thought was about 4 feet high.

At around 8 p.m., he said, went into the bedroom to change clothes. He heard a loud bang, and then the 3-year-old ran into the room crying and apologizing.

“He went into the living room and found [the 1-year-old] with a gunshot wound to her head while she was lying on the couch,” an arrest affidavit says. “Tejeda said he found his firearm lying on the couch next to [the child].”

The little girl was taken to Wesley Medical Center and was pronounced dead just before 9:30 p.m.

According to the affidavit, the children’s 24-year-old mother had gone to a friend’s, leaving Tejeda in charge. She told investigators that Tejeda called her and told her what happened, and she told him to call 911 as she raced back home.

The incident took place on February 28, and Tejeda was charged on March 1. The court documents revealing the details were released this week.