A 4-year-old girl was murdered by her father because he was angry about her mother's new boyfriend, Harris County Sheriff's investigators say.

Tarel Felder picked up his daughter, Amyira, from her mom's house in Louisiana and brought her to his mother's house in Katy. They had been there for a few days.

The mother told deputies she left to run an errand Thursday night and came home to find her son dead and her granddaughter wounded. Amyira was rushed by Life Flight to Memorial Hermann Hospital, but doctors couldn't save her.

Tarel Felder posted an eerie video on Instagram earlier Thursday.

"It's OK to have guns, but don't involve kids," said Urkia Lock. "It's terrible. It's very sad."

It happened in the 5400 block of Plantation Forest Drive just before 9 p.m. Thursday.

KHOU 11 News spoke with several neighbors, all of whom said they never saw or heard anything strange at the home.