Christian A. Torres’s neighbors in Queens remember his pride, how he stepped tall when he first wore the uniform of a New York City police officer.

He’d earned a 3.6 grade-point average at John Jay College of Criminal Justice while holding down one or two part-time jobs. He became a leader in the Police Department’s cadet program. In July 2007, he traded his books for a gun belt and joined the Police Academy. Six months later, he was on patrol in the Brooklyn subways.

But on Friday, Police Commissioner Raymond W. Kelly said that as he moved from cadet to recruit to probationary police officer, Christian A. Torres, 21, was something else as well:

A serial bank robber.

Officer Torres, police officials said, committed three robberies at two branches of Sovereign Bank  twice in Manhattan and once in Pennsylvania  apparently using some of the $118,305 for a new car, for a diamond engagement ring for his girlfriend and to pay off his student loans.

He grew increasingly brazen, the police said: at the first robbery, in June 2007, he simply handed a note to the teller demanding money. At the second, in November, they said, he showed a gun in his belt, which police described as an imitation weapon. At the third, on Thursday, he waved his personal 9-millimeter gun at three bank employees as he demanded cash in $20, $50 and $100 bills, the police said.