It sounded like a motorist's worst nightmare: a Californian estate agent, James Sikes, made headlines around the world last week when he recounted how his Toyota Prius went out of control on a San Diego freeway, reaching a speed of up to 94mph until a highway patrol officer guided him to safety.
Sikes's account is now under scrutiny as experts puzzle over technical discrepancies and details emerge of his colourful financial history.
Sikes became the face of Toyota's safety crisis as a flustered, white-haired 61-year-old, when he went public with his story and a recording was released of his panicky voice telling an emergency operator: "My car won't slow down!"
His ordeal appeared to be the latest, most dramatic, in a string of incidents involving faulty accelerators that has led Toyota to recall more than 8m cars around the world. But after extensive tests, the US government's national highway traffic safety administration today revealed it had not found anything wrong with the 2008 blue hybrid car.
"So far, we have not been able to find anything to explain the incident that Mr Sikes reported," the agency said. "We would caution people that our work continues and we may never know exactly what happened with this car."
Toyota has dismissed Sikes's story, saying its own tests found the car's accelerator and backup safety system worked. It stopped short of saying Sikes had staged a hoax, but said yesterday that his account did not square with a series of tests it conducted on the petrol-electric hybrid.
Toyota said its testing found Sikes had rapidly pressed the accelerator and brakes back and forth more than 250 times.
A spokesman, Mike Michels, told a press conference: "We have no opinion on his account, what he's been saying, other than that the scenario is not consistent with the technical findings."
Meanwhile, public records have revealed that Sikes has a troubled financial past. In 2006, he appeared on a television game show called The Big Spin and won $55,000. But two years later he filed for personal bankruptcy, citing debts of $115,000 on 16 credit cards.
Darrell Issa, a Californian congressman on the house oversight committee,, expressed reservations about the incident, saying that some cases of faulty vehicles arose from driver error, while others could be perpetrated by people seeking "notoriety". Issa said the government's test result "doesn't mean it didn't happen. But let's understand, it doesn't mean it did happen."
After weaving around cars and lorries, Sikes's high-speed journey came to an end when a highway patrol officer guided him through an emergency braking procedure and then positioned his patrol car in front of the Prius to slow it down.
Sikes's lawyer, John Gomez, dismissed doubts, saying that his client is not suing Toyota and has declined television appearances. Gomez added that the highway patrol officer could smell burning brakes and saw the car's brake light on.
"There's a ghost in the machine," Gomez told the Los Angeles Times, adding that Toyota has made little progress in pinpointing problems with other runaway cars. "No one is able to replicate it or identify it."
Sikes's wife, Patty, pleaded with reporters to leave the couple alone, saying they had received death threats.
"Our careers are ruined and life is just not good anymore," she said.