I remembered the controversy but looked it up on the web just to confirm all the details. Back in 1995, the Wayne County race shop was broken into at night and almost all of the teams Pro Stock engine components (mostly cylinder heads) were sledge hammered. The Wayne County team claimed they couldn't race for the remainder of the season due to the lack of parts following the break in. Warren Johnson made a big push during the remaining part of the '95 season and won the Pro Stock title. I also remember some rumors back then that the "break in" was actually orchestrated by Mopar to destroy the parts so that nothing could be proven - it was never proved one way or the other. Mopar wasn't competitive in Pro Stock racing for some time after that.
Here's what the web had to say:
The team was the factory Mopar team (Wayne County racing?), with drivers Darrell Alderman and the late Scott Geoffrion. The controversy was that they were alledgedly using nitrous. Suspicions came after an engine explosion with a very suspicious flame. Supposedly, the NHRA did nothing since Mopar provided the NHRA with a lot of advertising support, both in event sponsorship and tv ads, and the NHRA didn't want to publicly rat out/punish one of their biggest supporters, thus the supposed break-in/cover up. In the end, the first "official" nitrous user was Jerry Eckman, who after being caught with nitrous bottles hidden in his oil pan after a pit area explosion, was banned from the sport.