A Valdosta police officer shot a man who threatened her with a knife as she was trying to stop an assault, the Georgia Bureau of Investigation said Thursday.

According to GBI officials, Officer Alyssa Shirey got a call around 6 p.m. Wednesday about a domestic dispute involving child custody.

Shirey arrived to find Johnathan Lozano-Murillo attacking a woman at the home, officials said.

As Shirey tried saving the woman from the attack, Lozano-Murillo began walking toward her with a knife, according to GBI officials.

“Officer Shirey had attempted to use a Taser during the incident which was ineffective,” GBI spokeswoman Nelly Miles said in a release.

When that didn’t work, she shot Lozano-Murillo.

Lozano-Murillo was taken to a hospital, where he died from his injuries.

Officials did not release the race of Shirey or Lozano-Murillo. The investigation is ongoing.