Phoenix ? A serial rapist was sentenced Friday to 50 years in prison and began to sob after listening to some of his 13 victims testify about how the attacks had traumatized them.

David B. Wilson Jr., 33, pleaded guilty in a plea agreement last month to 13 felony counts of sexually assaulting or attempting to assault young women in the Phoenix area between July 2004 and July 2005.

“I have nightmares every night of your smell, your touch,” one woman who fought off Wilson and avoided being raped told the court.

The testimony brought Wilson to tears. After hearing from the victims, he choked back sobs, expressed remorse and said he was willing to have the plea agreement torn up and face a longer prison term.

“I hurt so many people,” he said. “I’m deeply sorry to all of you folks. It wasn’t your fault.”

Prosecutors kept the plea agreement intact. Detective Randy Hutson said that was in victims’ best interest so they would not have to testify at trial.

Police said Wilson would track his victims’ movements, sometimes for weeks. Authorities caught him skulking around a north Phoenix apartment complex in September 2005 after weeks of nighttime stakeouts.