A fired employee shot and killed his former supervisor and injured two other people Thursday at the sprawling apartment complex where he used to work, police said.

The alleged shooter, Paulino Valenzuela, turned himself in shortly after the attack at the Co-op City housing complex, said police spokesman Paul Browne.

Valenzuela was fired in February 2005 from his job as a porter at the massive housing complex for making threats against other employees, according to court papers. Last week, a judge ruled against him in a discrimination lawsuit brought against his former employer.

Police said that at about 8 a.m. Thursday, the shooter entered a basement office at the complex and shot and killed a 59-year-old employee, police said. After leaving the basement, he shot two other workers, authorities said.

One of the surviving victims was hospitalized in critical condition with a neck wound. The other was treated for a gunshot wound to the arm and released.

The sprawling Co-op City was built in the late 1960s on the site of a former amusement park. It includes 35 high-rises and seven town-house clusters, and has its own security force and power plant. Calls to the management company, RiverBay Corporation, were not returned.