Authorities say a 14-year-old boy shot and wounded his older sister and killed her boyfriend during “a house party gone bad” in a Houston suburb.

Harris County Sheriff Ed Gonzalez says on Twitter that the boy shot his 18-year-old sister and her 20-year-old boyfriend with a shotgun at a home in Katy around 11:40 p.m. Saturday.

Gonzalez says there had been a “disturbance” between the boy and his sister’s boyfriend, and that there were about 10 young adults in the home at the time.

He says the 14-year-old was detained but isn’t in custody. Investigators will refer their findings to a juvenile prosecutor.

The sister is in stable condition at a hospital. Her boyfriend was declared dead at the scene.

The sheriff’s department hasn’t responded to requests for comment Sunday.