INDIANTOWN, Fla. (AP) — A Florida woman was fatally shot by her ex-boyfriend as her daughter started her first day of online school, authorities said.

A Warfield Elementary School teacher told investigators she could hear some kind of domestic disturbance from her 10-year-old student's video chat Tuesday morning, Martin County Sheriff William Snyder said during a news conference. The teacher said she muted the audio from that student but then saw the girl cover her ears before the screen went blank. Investigators later confirmed that the computer had been struck by a bullet.

Donald Williams, 27, has been charged with first-degree murder in the death of Maribel Rosado Morales, 32. Investigators said Williams shot the woman multiple times at her Indiantown home in front of her four children and their two cousins.

“There was some type of argument. He went in and confronted her with something to do with a video,” Snyder said. “He says she actually started to smile at him, and he became enraged and shot her."

Williams fled the area on a bicycle and went to a nearby laundromat, officials said. He then boarded a commuter bus, but his erratic behavior prompted the driver to leave the bus and call 911, Snyder said. Williams was arrested shortly after that.

Besides the murder charge, Williams also faces two counts of aggravated assault, one count of burglary and one count of being a convicted felon in possession of a firearm. He was being held without bond. Jail records didn't list whether he had an attorney who could comment on the charges.