The bizarre tale began last March when Irvin was allegedly found in a Texas motel room with two former topless dancers and generous quantities of cocaine and marijuana. He was arrested and charged with drug offences carrying up to 20 years in jail, and Johnnie Hernandez, a much-commended member of the Dallas police force, was subpoenaed to give evidence.
However, Mr Hernandez'participation in the trial is now most uncertain. On Thursday, he was himself arrested and accused of paying $5,000 (pounds 3,500) to an undercover agent of the federal Drug Enforcement Administration as a downpayment on a contract on Irvin's life.
According to a Dallas police spokesman, Mr Hernandez handed over the money at a meeting with the DEA officer, posing as the hitman, in the parking lot of a shopping mall. He promised to pay a further sum after the murder, which he wanted "to occur very soon".
The rest remains a mystery. The spokesman would give no indication of Mr Hernandez' alleged motive. He is understood to have been scheduled as a defence witness, to testify about his relationship with Angela Renee Beck, one of the dancers.
Whatever Mr Hernandez's involvement, the stunning turn of events makes it even less likely the Irvin trial will go ahead on time. Even before, his fame was holding up jury selection, as half the prospective jurors identified themselves as Cowboys fans and one said her daughter was "infatuated" with Irvin.
More ominous, perhaps, is the presence of the DEA. Over the last few years, in which Irvin helped the Cowboys to win three out of four Superbowls between 1993 and 1996, several players have been in trouble for drug and alcohol abuse and for mistreating women. That a federal agency is pursuing the Irvin case suggests the DEA suspects an organised drug-dealing scheme for star players.
If convicted, Irvin, 30, could be sent to prison for up to 20 years. "I don't have anything to say," he said on Thursday evening, accompanied by five bodyguards. But his colleague, the Cowboy's legendary running back, Emmitt Smith, said: "It makes you think about things ... No matter how tight the security, they got JFK, and they got Bobby Kennedy too." The former of course in Dallas.
As for Mr Hernandez, who resigned from the force after being charged with solicitation of capital murder, he faces a maximum of 99 years behind bars.