Jamon Allen went to prison Tuesday for a murder that he insists he did not commit.

Allen, 32, was sentenced to life without parole for the shooting death of Duncan Walker in Des Moines nearly two years ago. The sentencing, which followed a minor outburst from Allen's family after the trial verdict earlier this month, took place in a secure courtroom at Polk County Jail with only lawyers and court officials present.

Testimony during the trial showed that Allen, roughly a week before Walker's death, had threatened to get a gun and shoot his wife.

But Sheila Allen said Monday that her husband wasn't as jealous as Polk County authorities made him out to be.

"In a relationship, everyone has problems," she said. "I dated other people, and Mr. Allen has never confronted any of them."

Polk County prosecutors say mobile phone records and police interviews show Allen called his girlfriend shortly after the shooting to establish an alibi. Allen's children also told police early on that they thought they heard their father's voice before the shot.

Allen's lawyers insisted during the trial that police had ignored other possibilities and that Sheila Allen's relatives had steered the children into saying that their father was in the house.

Jurors convicted Allen of first-degree murder after less than one day of deliberation.