Police recovered the gun at Graham's parents' home.With the evidence seemingly so clear-cut, Graham's hometown of Mansfield, and Crowley, where Zamora lived, are stunned. The couple's American-dream- come-true had featured in the local papers.He was, in the words of his lawyer Dan Cogdell, a "straight-A, pick-of- the-litter kid, who had never done anything wrong in his life".The reputation of Zamora, who appears to have been the driving force behind the crime, was scarcely less.Graham's lawyer now says his client did not pull the trigger, and that his confession was co-erced. Graham then pulled out a 9mm pistol and shot her.The two accomplices left her body and fled. On the night of 3 December 1995, Graham arranged to meet Jones and came to collect her at her home in a pick-up truck, in which his girlfriend was hiding.They drove to the deserted lake where the killing would take place.

The original scheme was to sink Jones' body in the lake.But when Zamora climbed down from the back of the truck and attacked her with a barbell, Jones escaped. And, Zamora is said to have insisted, the only way to expunge it was to remove every trace of it, "if you want to solve this problem, we have to make sure she doesn't exist".And so they devised their plan. The fling, he said in his confession to police obtained by a Dallas newspaper, was an "unclean act" that soiled the "purity" of his long-standing relationship. At first he maintained the murder was a fiction, but after he failed a lie detector test, he confessed He now awaits extradition from Colorado to Texas. His girlfriend is in jail, in lieu of a $250,000 (pounds 165,000) bond. And their crime, it is clear, is not one of headstrong teenage passion but of coldblooded, carefully plotted revenge.According to Grand Prairie police, a remorseful, guilt-stricken Graham quickly told Zamora of his tryst with Jones.

A young man at Mansfield, where Graham and Jones were at high school, was briefly arrested, but released for lack of evidence. As the months went by police lost hope, until last week the answer emerged more than 1,000 miles away.Diane Zamora, now in her first term at the US Naval Academy in Annapolis, Maryland, took part in a tell-all session with her two room-mates, discussing the worst thing each had ever done. Initially Zamora maintained she had made her story up, "to gain sympathy and attention", and in the absence of conclusive evidence she was sent home to Texas.Then the police interrogated Graham, by now a first-year cadet at the no less blue-riband US Air Force Academy in Colorado Springs. Scarcely less puzzled, the academy informed police departments around Fort Worth The unsolved killing at Grand Prairie seemed to fit.