Public hearings begin in Illinois today into how a mass murderer who was jailed for life for the killings of eight student nurses in 1966 was allowed to lead a life of sex and drugs while behind bars - and make a film about it.

At issue will be a video aired by a Chicago television station that shows Richard Speck, one of America's most notorious killers, cavorting around an Illinois maximum-security jail in women's underwear, engaging in sex with male inmates and snorting a white powder that appears to be cocaine.

"If they only knew how much fun I was having here, they would turn me loose," Speck boasts to the camera.

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With viewers enraptured and appalled by the tape, it has exposed public suspicion that even those convicted of the most heinous crimes enjoy liberal treatment inside prison. The controversy is set to become nationwide this weekend, when the video will be broadcast by the A&E cable channel.

Apparently made with video equipment which was kept in the jail for guard training, the tape was produced in 1988.

At one point it shows Speck, who died of a heart attack in 1991, stripping out of his jumpsuit to reveal blue women's undergarments.

Segments during which he engages in oral and anal sex acts were not broadcast by the television channel.

Speck also confesses on camera for the first time to the murder three decades ago of eight student nurses in Chicago's South Side during a burglary. At trial, he claimed ignorance of the murders because of drug-induced amnesia.

Today's hearings in the Illinois State legislature will investigate how such behaviour by a convicted murderer was possible within the prison system. "Who is minding the store here? How can this stuff go on so that you can even make movies without the system being aware of it?" asked a state representative, Thomas Johnson, who will chair the hearings.

Peter Roskam, another state representative said: "The notion that you could do these things in the Illinois Department of Corrections is absolutely insidious."

Questions are also being asked whether Speck was illicitly supplied with female hormones while in prison. On the tape, he appears to have developed ample female breasts.