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 was identified as Freddy Batt Sosa.

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, who were in one patrol car, were dispatched to where a man and woman were physically fighting near the parking lot of the center, Widmer said.

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

Detectives also found out that Sosa was armed with a black Stinger P311 BB gun, which looks like a handgun, Widmer said. Some such BB guns have orange tips; the one Sosa had did not.

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.

Corrales and Tapia arrived within two minutes of the call.

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

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

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

Sosa was pronounced dead at the scene.

His sister, whose name was not released, 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 criminal aspect of the shooting, and internal affairs is conducting an administrative investigation to determine if proper department procedures and policies were followed.