"I'm going to show you both of the Carfaxes," he said. "I'm going to show you everything."
Both vehicles' reports showed no accidents or damage reported to Carfax.
"When you look at the Carfax -- no accidents, one owner," the salesman said. "You can't beat that Carfax."
The salesman's boss chimed in.
"The Carfax'll tell you if it's been in an accident. It basically gives you the history of the vehicle of where it's been and stuff like that. You know, we don't keep anything on our lot that has accidents," he said.
In fact, according to one of Carfax's competitors, Autocheck, the Hyundai had been in a rear-impact collision. And the Mazda had been in a multiple-impact collision -- the police report said it had been hit in the front and the back. ABC News also contacted the car's former owner, who said he was in the accident and confirmed that they were the middle car, so the car got hit on both sides.
It wasn't just this one dealer. The ABC News investigation revealed dozens of used cars with clean Carfaxes -- even though the cars had been in accidents, and others had frame damage, according to Autocheck. Like Carfax, Autocheck also includes a disclaimer about its comprehensiveness, but it does boast one important source of information that Carfax doesn't have: Car auction data.
ABC News returned to the New Jersey dealership, armed with the police report saying the Mazda had been in a major accident.
The salesman defended himself by saying, "I don't get under the hood of these cars or anything like that. I print out the Carfax. ... If I print out a Carfax and it says that it's green, that means the Carfax is 100 percent."
When asked if there was a problem telling us that the clean Carfax he showed us actually meant no accidents (as opposed to none reported to Carfax), the salesman said, "You have to take that up with the Carfax. You got to take that up with the Fox himself, I mean."
At least one family -- the Chaneys -- said they wouldn't be outfoxed again.
"The commercials have so much hype to them," Danny Chaney said. "I won't trust Carfax. And I will tell everyone I know, Don't trust Carfax."
Note: Since this story was published, Carfax informed ABC News that they have updated the Carfax reports for the following vehicles mentioned in the story: the 2012 Chevrolet Colorado, the 2011 Mazda CX-7 and the 2011 Hyundai Sonata.