His 1977 season was arguably the greatest ever by a Michigan State football player, when he totaled 45 solo tackles, 45 assisted tackles and 16 sacks, becoming such a dominant force that he was the first defensive player to receive Big Ten Conference MVP honors since Dick Butkus in 1964.
Bethea finished his college career as a three-year starter, with school records in: career sacks (33), career tackles for loss (43) and sacks in a season (16).
Bethea played defensive end and defensive tackle, but his production started to dwindled as his personal problems and addictions grew bigger. Although he remained with the Cowboys for six years, he failed to become a starter and live up to his potential.
His most notable play was stopping Ram's running back Cullen Bryant at the Cowboys 11 yard line on 4th and one during the 3rd quarter of the 1978 NFC Championship game .
Bethea was rumored to have a drug abuse problem dating back to his college days, and cocaine addiction was blamed for the problems he had during his adult life.
His troubles with the law began in 1985 when he pleaded guilty to setting three fires in Mount Rainier National Park in Paradise Washington. He was ordered to pay $1,000 to the park to cover the cost of fighting the fires.
In 1986, he was jailed on charges of assaulting his wife and stealing his mother's life savings of $64,000. In 1987, he was given a suspended four-year prison term for stealing. The judge also ordered Bethea to serve two years on probation while repaying the money.
In the final incident, on April 24, 1987, police were called by an unidentified source who said the former football player had robbed two convenience stores. Bethea, 30, was later found in a friend's backyard with a self-inflicted gunshot wound to his right temple and a .38-caliber automatic pistol near his body. He was taken to Hampton General Hospital, where he was pronounced dead at 2:08 a.m. The gun used in the shooting and the two robberies was believed to be a weapon that was reported stolen from a parked vehicle in the city.