(NewsNation) — Florida police on Wednesday arrested a 14-year-old accused of fatally shooting his adult sister and threatening to fire at her infant son during an argument over Christmas presents.

The situation began on Christmas Eve when 23-year-old Abrielle Baldwin went shopping with her mother, two teenage brothers, and her 11-month-old and 6-year-old sons.

They returned to their grandmother’s house and an argument broke out about how many gifts each child was getting, Pinellas County Sheriff Bob Gualtieri said during a news conference.

When Baldwin told her 14-year-old brother to stop arguing, he threatened to shoot her and the 11-month-old boy she was holding in a carrier, according to a news release. The teenager fired at his sister, shooting her in the chest while she was holding her son, police said.

Baldwin’s other brother, 15, then shot the 14-year-old and fled the area, according to the news release.

Both Baldwin and the brother accused of shooting her were taken to a local hospital, where the 23-year-old mother of two was pronounced dead.

The 14-year-old remained in the hospital as of Wednesday. He is charged with first-degree murder, child abuse and being a delinquent in possession of a firearm.

Officials transported the 15-year-old to a mental health facility. He is charged with attempted first-degree murder and tampering with physical evidence.

Police haven’t located the gun they say he used to shoot his younger brother.

It’s unclear whether prosecutors will charge the boys as adults.

Local teenagers have been obtaining guns either by purchasing stolen firearms off the street or stealing them during car burglaries, Gualtieri said.

“In the last thirty days, we’ve taken reports where seventeen guns have been stolen from unlocked cars,” he said. “Help us because we have a problem. Lock your doors.”