Atlanta ? Pro wrestler Chris Benoit suffered head trauma from his years in the ring that could help explain why he killed his wife, son and himself, a doctor who studied his brain said Wednesday.

The analysis by doctors affiliated with the Sports Legacy Institute suggests that repeated concussions could have contributed to the killings at Benoit’s suburban Atlanta home, though there was no way to know for sure.

“Whether it is the sole factor, I believe, is speculation, and I will not go there,” said Dr. Robert Cantu, a member of the Waltham, Mass.-based institute, which researches the long-term effects of concussions.

The level of brain damage Benoit had could have caused depression and irrational behavior, said Cantu, who also is chief of neurosurgery service at Emerson Hospital in Concord, Mass.

The wrestler’s father, Michael Benoit, said Wednesday he agreed to the testing of his son’s brain because murder-suicide was so out of character. He said his son complained about suffering concussions, but that he knows of no medical records or records kept by the wrestling league to support the diagnosis.

Steroid use also has lingered as a theory behind the killings, since anabolic steroids were found in Chris Benoit’s home and tests conducted by authorities showed Benoit had roughly 10 times the normal level of testosterone in his system when he died.

Some experts believe that use of testosterone can contribute to paranoia, depression and violent outbursts known as “roid rage.”