Late WWE champion Chris Benoit injected his seven-year-old son, Daniel, with a growth hormone so as to prevent him from growing undersized.

The young boy, who was killed along with his mother Nancy by Benoit before the fighter committed suicide, was found with needle marks in his arms.

Fayette County District Attorney Scott Ballard has also confirmed that confirmed Daniel had been given growth hormones for some time, as the late couple considered their child to be undersized.

'The boy was very small, even dwarfed,' the Sun quoted him as saying.

The newspaper also reports that Daniel had Fragile X Syndrome, a condition that can lead to behaviour problems, autism and hyperactivity and, in some cases, mental retardation.

Benoit kept taking steroids throughout his career because he was worried about losing his job due to his size, which was a lot smaller than the typical wrestling superstars.

'This was decades and decades of steroid use with no cycling - even when undergoing neck surgery. And that's not healthy in any way,' said a source.

Cops probing the case have also revealed that Benoit illegally obtained steroids, human growth hormone, and testosterone on the Internet from a Florida business called MedXLife.com.

So far six people have pleaded guilty to supplying Benoit with drugs, 20 others have been arrested for further interrogation.

Ever since Benoit's friend and fellow MedXLife.com customer Eddie Guerrero died of heart failure in November 2005, the WWE has been observing a strict testing procedure. However, the company's 'Wellness Policy' allowed for prescribed steroids.

'The WWE policy prohibits the use of performance-enhancing drugs, as well as other prescription drugs which can be abused, if taken for other than a legitimate medical purpose pursuant to a valid prescription from a licensed and treating physician,' it said.

A statement issued by the WWE said that there was no evidence to suggest that Benoit had steroids in his blood at the time of killings.

'Steroids were not, and could not, be related to the cause of death (asphyxiation). Authorities had no factual basis to speculate as to Benoit's state of mind, and rightly did not do so,' said the statement.

'A full Toxicology (blood test) report has not even been completed, so there is no current evidence that Benoit even had steroids or any other substance in his body,' the statement added.