PORTLAND - A New Yorker who killed a man after a deal for an ice-cream truck went bad pleaded guilty to aggravated murder and will be sentenced to life in prison next month.

Opening statements in Tremayne Durham's death-penalty trial were supposed to start later this week, but the Brooklyn man agreed to a plea that will give him the chance for parole after 30 years.

Durham, 33, fatally shot Adam Calbreath of Gresham in June 2006 after coming to Oregon to look for Rob Chambers, who builds and customizes ice cream trucks.

Six months before the shooting, Durham contacted Chambers from New York about building him an ice cream truck. Durham later came to Gresham, where Chambers lived at the time, and paid him $18,000 in cash.

In the next few months, they talked by phone and e-mail, but the progress was too slow for Durham, who changed his mind and wanted his money back.

Chambers, however, told him he had signed a contract and couldn't get a refund.

In that time, Chambers moved from Gresham to Portland. But Durham did not know that.

Police believe Durham traveled back to Oregon by bus and train to seek revenge. Authorities don't know exactly why Durham killed Calbreath, only that he probably found the former employee's Gresham address on the company's Web site.

Durham shot him in the head, using a pillow to silence the sound.

Calbreath's murder remained a mystery for 12 days, until Durham showed up at Chambers' Portland house with the same gun he used to kill Calbreath. He also brought duct tape and handcuffs.

Durham demanded his money back plus thousands extra, prosecutors said.

The banks were closed because it was a Sunday, and Chambers was able to convince Durham that he'd get his money the next day. Deputy District Attorney Josh Lamborn credited Chambers with keeping his cool and talking Durham into believing him.

"I really think that's what saved Rob's life," Lamborn said Tuesday.

Chambers started playing a movie for Durham and persuaded Durham to let him leave the house.

Chambers then called Portland police.

Durham, a convicted felon who served time in prison for rape, is scheduled to be sentenced Aug. 6.