A man armed with a BB gun who was fighting with his sister was shot and killed by two Tucson police officers Saturday night on the south side.

The man, Freddy Batt Sosa, 22, was fatally wounded while at El Pueblo Regional Center, 101 W. Irvington Road, said Sgt. Chris Widmer, a Tucson Police Department spokesman.

The shooting happened shortly after 7 p.m. when Sgt. Will Corrales and Officer Jesus Tapia were dispatched to the scene of a man and woman fighting near the center's parking lot, Widmer said.

During their investigation, detectives found out that Sosa was fighting with his sister.

Detectives also found out that Sosa was armed with an all-black Stinger P311 BB gun, which looks like a handgun, Widmer said. Other such BB guns often have orange tips.

The 911 caller reported that the man had a gun, and at one point had the woman down on the ground with the gun pointed at her, said Widmer.

As the officers got out of their patrol car, Corrales saw what he thought was a gun in Sosa's waistband, said Widmer.

There was a confrontation between the officers and Sosa, who began walking toward the officers and removed the gun from his waistband, Widmer said.

Corrales and Tapia both fired their guns at Sosa, striking him. The officers administered first aid until Tucson Fire Department paramedics arrived, said Widmer.

Sosa was pronounced dead at the scene. His sister, who was not identified, was not injured.

Corrales is a 16-year veteran of the Police Department, and Tapia was hired in September 2012, said Widmer.

As standard procedure in officer-involved shootings, both officers were placed on administrative leave.

Homicide detectives are investigating the shooting, and internal affairs is conducting an administrative investigation to determine if department procedures and policies were followed.