DECATUR, Ga. - Pro wrestler Chris Benoit had a steroid and other drugs in his system when he killed his wife and young son last month and hanged himself in the family's home, investigators said Tuesday.

This March 29, 2004 file photo provided by World Wrestling Entertainment shows Chris Benoit. [AP]

Benoit's body contained 10 times the normal level of testosterone, as well as amounts of the anti-anxiety drug Xanax and the painkiller hydrocodone, authorities said.

The testosterone, a synthetic version of the primary male sex hormone, is considered an anabolic steroid. The state's top medical examiner said it appeared to have been injected shortly before Benoit died.

Dr. Kris Sperry said there was no evidence of any other steroids in the wrestler's body, and nothing to show that steroids played a role in the death of Nancy and Daniel Benoit. He also said the boy appeared to have been sedated when he was asphyxiated, and Benoit's wife had a "therapeutic" level of sedatives in her body.

Sperry said there is no consensus that the use of testosterone can contribute to paranoia, depression and violent outbursts known as "roid rage."

"This a question that basically no one knows the answer to," Sperry said. "There is conflicting scientific data as to whether or not testosterone creates mental disorders or leads to outbursts of rage," he said. "There's data that suggests it and other data that refute it."

The Georgia Bureau of Investigation said Chris Benoit tested negative for alcohol. Investigators had been eager to determine whether alcohol was a factor in the killings after 10 empty beer cans were found in the home, as well as an empty wine bottle a few feet from where Benoit hanged himself.

Benoit killed his wife and 7-year-old son, placed Bibles next to their bodies and then hanged himself on the cable of a weight machine. After the slayings, prescription anabolic steroids were found in the family's home, raising questions about whether the drugs played a role in the killings.

Benoit's wife, Nancy, tested positive for Xanax, hydrocodone and the painkiller hydromorphone. Daniel Benoit had Xanax in his system, authorities said. The GBI said it could not perform tests for steroids or human growth hormones on the boy because of a lack of urine.

Nancy Benoit's body had a blood-alcohol level of 0.184 percent, more than twice the level at which Georgia law considers a driver intoxicated. But, Sperry said, that level may have been affected by decomposition.

Federal authorities have charged Chris Benoit's personal physician, Dr. Phil Astin, with improperly prescribing painkillers and other drugs to two patients other than Benoit. He has pleaded not guilty.

Investigators have also raided Astin's office several times since the deaths, seizing prescription records and other documents.

Before he was charged, Astin told the AP he prescribed testosterone for Benoit, a longtime friend, in the past. He would not say what, if any, medications he prescribed when Benoit visited his office June 22, the day authorities believe Benoit killed his wife.

World Wrestling Entertainment last screened Benoit for steroids in April. It said the results released Tuesday were proof Benoit did not test positive for illegal substances.

"All it means is that scientifically, it's now known that sometime between April 10 and when he died, he had treatment with testosterone," said Jerry McDevitt, a WWE attorney. "That's all it establishes."