Questions are being asked about whether anabolic steroids may have been a contributing factor in the murder-suicide deaths of Canadian pro wrestler Chris Benoit and his family.

Benoit -- 180 centimetres tall and weighing 100 kilograms -- strangled his wife and suffocated his son before hanging himself with a pulley on a weightlifting machine, a law enforcement official said Tuesday.

"From an investigation that has taken place yesterday afternoon, and continued at the crime lab earlier today where autopsies were performed on all three subjects, we're now looking at this case and ruling it as a double homicide-suicide," said Lt. Tommy Pope, lead investigator with the Fayette County Sheriff's Department.

Pope said evidence from Benoit's suburban Atlanta home led investigators to believe that the one-time world champion murdered his 43-year-old wife Nancy, possibly on Friday. Sometime shortly after that, Benoit murdered his seven-year-old son Daniel.

"Then maybe later on Saturday evening, sometime early Sunday, he committed suicide by hanging himself in the basement," said Pope, adding that no suicide note was found at the scene.

Benoit was supposed to participate in a pay-per-view World Wrestling Entertainment event in Houston over the weekend but cancelled because of a family emergency.

Friends of Benoit said they received "curious text messages" from the wrestler on Sunday morning. One said his wife and child were sick, and the other said the doors were open and the pets were outside.

The WWE notified authorities after hearing from friends who received the messages, the wrestling organization said on its website.

Benoit, 40, his wife and son were found dead at 2 p.m. on Monday in three separate rooms. Police said Benoit placed a Bible next to the bodies of his wife and son before hanging himself. All three died of asphyxiation, autopsy results show.

"I'm baffled about why anybody would kill a seven-year-old, said District Attorney Scott Ballard."I don't think we'll ever be able wrap our head around that."

Daniel had needle marks on his arms. His parents considered him under-sized and had injected him with growth hormones, Ballard said.

Investigators found anabolic steroids in the house.

Steroids can cause paranoia, depression and explosive outbursts known as "roid rage."

A wrestler who toured with Benoit for years said he's seen the harm steroids can cause. "One little thing goes wrong and you're going to see an outburst, a rage," said Jacques Rougeau.

WWE issued a news release Tuesday decrying the speculation about steroid use being behind the tragedy.

WWE noted that investigators believed the drugs found were legally prescribed and that Benoit's actions indicate he killed in deliberation, not rage. Toxicology tests haven't been completed yet.

"WWE strongly suggests that it is entirely wrong for speculators to suggest that steroids had anything to do with these senseless acts."

Other professional wrestlers' deaths have been linked to long-term steroid use. However, none of those individuals were suspected of killing anyone.

Benoit a 'family man'

Benoit was born in Montreal and grew up in Edmonton, graduating from Archbishop O'Leary High School.

He began his career in 1985, starting with the famous Hart family of Calgary, who operate Stampede Wrestling.

Five-time champion Bret Hart called Benoit a "beautiful man" who "loved his son" and was a credit to professional wrestling.

"It's so hard for me to get my head around what happened, and I don't think it's even hit home yet how horrible all this is," Hart told CTV Newsnet from Calgary on Tuesday evening.

"I don't know what brought it on, ... but my understanding from Chris is that he was a happy, proud father and family man and he gave everything he had to wrestling and his fans ... This is not something that was characteristic of Chris Benoit."

Benoit won the world heavyweight championship at Wrestlemania XX. In response, Edmonton declared "Chris Benoit Day" on April 15, 2004.

Benoit was known as "The Canadian Crippler," in part after he unintentionally broke another wrestler's neck during a match in 1994. Another nickname was the Rabid Wolverine. His signature move was the "Crippler Crossface."

The Atlanta Journal-Constitution reported Benoit's wife, known by her stage name "Woman," managed several wrestlers.

The couple met when Chris Benoit wrote a script depicting an ongoing love affair between the two on World Championship Wrestling, the newspaper said.

Nancy Benoit filed for a divorce in May 2003, saying their three-year marriage was irrevocably broken and alleging "cruel treatment." She later dropped the complaint, as well as a request for a restraining order, in which she charged that Chris Benoit threatened her and had broken furniture in their home.

In the divorce filing, she said Benoit made more than US$500,000 a year as a professional wrestler and asked for permanent custody of Daniel and child support. In his response, Benoit sought joint custody.

Benoit has two other children from a prior relationship.

With a report from CTV's Jed Kahane and files from The Canadian Press and The Associated Press