HOUSTON (KIAH) — A neighbor shot and killed a man who shot his own mother multiples times in their north Houston apartment, authorities said.

It happened around 12:45 a.m. Tuesday morning near Highland Cross Drive and Trevor Way.

Deputies with the Harris County Sheriff’s Office learned a mother and son were in their apartment when the son had been drinking and started acting strange.

He began shooting in the apartment and shot his mother several times, deputies said. A neighbor who lives in the complex got his firearm and then confronted the suspect.

The neighbor shot and killed the son because he believed the suspect was going to kill his mother, investigators said.

The mother was taken to a hospital in critical condition.

Homicide investigators are working to sort things out and the case will be referred to the Harris County District Attorney’s Office at completion, Harris County Sheriff Ed Gonzalez said.