Phoenix ? A gunman wounded two workers outside an office Thursday, and a man who recently worked in the building as a security guard was charged in the attack.

Michael Blas Rivera surrendered at his apartment complex, roughly six miles from the Pitney Bowes office where the shooting occurred more than two hours earlier, police said.

Rivera, 31, had worked at the office as a contracted security guard but quit Oct. 19, according to his former employer, Securitas Security Services USA Inc. Detective Stacie Derge said he pulled up in a car in the office’s parking lot, exited the vehicle and fired a semiautomatic rifle at two people outside.

The victims, a 29-year-old security guard who replaced Rivera and a 37-year-old assistant manager for Pitney Bowes, were taken to the hospital in critical condition.