OKLAHOMA CITY (AP) — An Oklahoma pharmacist convicted of murder in the shooting death of a teenager who tried to rob the south Oklahoma City pharmacy where he worked was sentenced to life in prison with the possibility of parole Monday in spite of his defense attorney and supporters' pleas that he be set free.

Jerome Ersland, 59, showed no emotion as District Judge Ray Elliott imposed the sentence recommended by a 12-member jury that found Ersland guilty of first-degree murder in the May 19, 2009, shooting death of 16-year-old Antwun Parker during an attempted robbery at the Reliable Discount Pharmacy.

Ersland claimed he was defending himself and two female co-workers when he shot Parker after he and a second teenager came into the pharmacy wearing ski masks and demanding money and drugs. Parker, who was unarmed, was struck in the head and knocked out. Ersland chased the second armed teen, Jevontai Ingram, now 16, out of the store.

Prosecutors said Ersland was justified in firing the first shot but went too far when he grabbed a second gun and fired five more bullets into Parker's abdomen, wounds that the Medical Examiner's Office said killed him. Ersland claimed the unconscious teen was still moving.

Ersland, shackled at the hands and feet in a jail-issued jumpsuit, stood before Elliott while defense attorney Irven Box asked the judge to suspend the life sentence. When the judge asked if he had anything to say, Ersland replied: "I don't have anything to say. Thank you."

Later, as he was led from court by sheriff's deputies, he responded to a reporter's shouted question by calling the sentence "an injustice of a monumental proportion."

District Attorney David Prater had opposed a suspended sentence and said Ersland was found guilty by a "stoic and serious jury" that has been criticized by bloggers and others who didn't see the evidence or hear the testimony in the case.

"Me and my office have been criticized. Even the defense team has been criticized," Prater said. "The rule of law applies. No one is above it."

Ersland's son, Jeff, was in court when his father was sentenced. He said he and others will continue collecting signatures on a petition that expresses outrage over the verdict and urges Gov. Mary Fallin and others to "please help us right this wrong." Petitions containing the names of about 17,000 people were delivered to Fallin's office last week.