According to police, a man killed two women and a 4-year-old girl and injured two children in a Baldwin Park neighborhood on Monday night.

The incident occurred when a man started arguing with his mother and shot her with a handgun afterwards, according to Lt. Daniel Rosenberg of the Los Angeles County Sheriff's Department.

The man then went next door and shot his neighbor and the 4-year-old girl.

The two injured children were a boy of 14 and a girl of 9 years old. Rosenberg said that she was in critical condition, Los Angeles Times reports.

A man was arrested by police when was found standing in the street with a handgun. The gunfire started around 7:30 p.m.

Rosenberg said: “We believe the suspect who was detained got into some type of argument with his mother, shot and killed her, then went next door on some type of a shooting rampage and shot his neighbors,” the Associated Press informs.

The gunman was not identified by authorities.

According to Capt. Mike Taylor of the Baldwin Park Police Department, the names of the two women were not released by investigators, neither were children’s names.

A deputy with the Sheriff's Department said that the two injured children were taken to a hospital.

The scene of the shooting, near North Park High School, was closed by police on Monday night. The scene was guarded by police and detective unites as the weapon and the bodies of the victims remained there.

The neighborhood, located at about 20 miles of Los Angeles, is known to be a quiet one, safe for the families with children who play in the front yard, so this incident comes as a surprise for the residents.