Austin Harrouff
Austin Harrouff, 19, has been released from hospital two months after police said he killed a Florida couple and gnawed on one of the bodies. Courtesy Martin County Sheriff's Office

The attorney for suspected 19-year-old cannibal killer Austin Harrouff said his client was likely suffering from the "onset of mental illness" when police said they found him grunting and gnawing on the face of one of two murder victims in a Florida garage.

"There are only a few narratives that could apply here," said attorney Robert Wilson after his client was charged in a Martin County courtroom on two counts of murder and one of attempted murder for an attack on a neighbor who tried to save the victims. "It does appear to have been an onset of a mental illness."

Whether that "mental illness was also coupled with other behaviour, I don't know that," he added, reported the Palm Beach Post. "I'm not the type of person to speculate about that.

"I realise people want answers, people want to guess about this thing. But I like facts, so let's find facts."

Police suspected Harrouff was high on some kind of bath salts or flakka drugs the evening of 15 August when officials say the college student suddenly viciously attacked a couple he didn't know who were sitting relaxing in their open remodeled garage on a street in Tequesta.

Harrouff exhibited superhuman strength when police arrested him and it took a police dog, four deputies and several jolts with a stun gun to subdue him.

Harrouff was rushed in critical condition to a nearby hospital, where he stayed for two months for organ failure caused by a mystery substance doctors believe he ingested — either toxic drugs or caustic chemicals he may have found in the garage where the murders took place.

His father, Wade Harrouff, has said he believed his son suffered some kind of mental breakdown possibly triggered or made worse by some kind of "poison." He said there are others in the family with mental illness.

Shortly before the murders Harrouff had talked about taking steroids and discussed his "psycho side" in a YouTube video.

The results of FBI blood tests are still pending.

Harrouff appeared in court with his attorney Tuesday (4 October). He was denied bail and will remain in Martin County jail.

He said nothing in court and has not spoken to authorities, said Martin County Sheriff Bill Snyder.