STRANGE HOLD: Benoit killed himself by wrapping a cord around his neck that was attached to a weight machine. -- PHOTO: AP

'As we went back to the time line of events, it became pretty obvious from several different sources that Nancy and Chris had tension in their relationship,' said Mr Jerry McDevitt on Wednesday.

'I don't know what they said to each other, but they were constantly struggling with the difficulties of raising a child who, from all indications, may well have had Fragile X Syndrome.'

Fragile X Syndrome is a rare inherited form of mental retardation that is often accompanied by autism.

Last weekend, Benoit, 40, killed his wife Nancy, 43, and their son Daniel, seven, and placed Bibles next to their bodies. He then hanged himself using a weight-machine pulley. The bodies were found on Monday at their suburban home near Peachtree City.

Mr McDevitt said Benoit's wife didn't want him to quit wrestling, but she 'wanted him to be at home more to care for the kid. She'd say she can't take care of him by herself when he was on the road'.

The couple had told friends and their physician they were worried about where to send Daniel to school since he had recently finished kindergarten.

He appeared to have been killed in a chokehold as he had internal neck injuries but no visible bruises, said Mr Scott Ballard, district attorney for Fayette County on Wednesday.

Nancy had bruises on her back and stomach, indicating her husband had his knee in her back as he pulled on a cord that was around her neck.

Benoit killed himself by wrapping a cord around his neck that was attached to a weight machine. He released the weights - about 108kg - to cause strangulation, Ballard said.

'The time gap between the death of Nancy and the time he was with this child, it doesn't take much to figure out what was going on in his mind,' Mr McDevitt said. 'The mother can't take care of Daniel, he'd killed her. He was going to jail. There was nobody left to take care of this little boy.'

Anabolic steroids were found in Benoit's home, leading officials to wonder if the drugs may have caused him to kill.

The WWE said steroids 'were not and could not be related to the cause of death' and that the findings indicate 'deliberation, not rage'. It also added that Benoit tested negative on April 10, the last time he was tested for drugs.

Also on Wednesday, his personal physician said the wrestler did not give any indication he was troubled when he met the doctor hours before the start of the weekend.

Benoit had been under the care of Dr Phil Astin, a longtime friend, for treatment of low testosterone levels. The doctor said the condition likely originated from previous steroid use.

He had prescribed testosterone for Benoit in the past but would not say what, if any, medications he prescribed the day of their meeting.

'He was in my office on Friday to stop by just to see my staff,' he said. 'He certainly didn't show any signs of any distress or rage or anything.

'I'm still very surprised and shocked, especially with his child Daniel involved. He worshipped his child.'

Meanwhile, the authorities in Georgia were investigating a link between Benoit and a Florida business that may have supplied him with steroids.

Prosecutors in upstate New York said he received deliveries from Signature Pharmacy and MedXLife.com, which sold steroids, human growth hormone and testosterone on the Internet.

While steroids can cause paranoia and explosive outbursts, the drug is also associated with deep and lengthy bouts of depression.

'Just as you have the extreme high of when you're on steroids, you can get the opposite,' said Dr Todd Schlifstein, a clinical assistant professor at the New York University School of Medicine. 'You can have a dramatic difference in mood swings. You can feel there's no hope, there's no future.'

NYT, AP