'Cannibal Killer' Student Austin Harrouff Regains Consciousness

A Florida student accused of randomly killing a couple and biting the dead husband's face has regained consciousness, investigators say.

Austin Harrouff, 19, is responsive, but has not yet provided a statement, according to the Martin County sheriff's office.

The Florida State University sophomore had been heavily sedated since the 15 August stabbings of 59-year-old John Stevens and Michelle Mishcon, 53.

Sheriff William Snyder says the former high school football player and wrestler will be charged with murder once he is discharged from hospital.

Investigators say he attacked his victims, whom he did not know, at the garage of their home in the affluent coastal town of Tequesta, 20 miles from Palm Beach.

The rampage began after Harrouff stormed out of dinner at a local sports bar with his parents in an apparent rage over slow service.

Investigators say he launched a completely unprovoked attack on the victims after wandering the streets for 45 minutes.

Multiple "weapons of opportunity" were used to beat, slash and attack the couple, including a switchblade the suspect was known to carry, said police.

A neighbour, Jeff Fisher, was badly injured after trying to intervene, before calling 911.

Radio transmissions show Florida sheriff's deputies were confronted with a chaotic scene as they tried to subdue the "abnormally strong" student.

When a dispatcher asked the first deputy on the scene if she had the suspect controlled, she responded: "No sir, I have this guy wrapped around him and he is biting him."

The police officer used her Taser on Harrouff to try to get him off Stevens' bloody body, but the stun gun didn't faze the attacker.

Sheriff William Snyder has said it took a number of deputies and a dog to pry Harrouff off Mr Stevens.

The victim's wife lay nearby.

Harrouff was making grunting, growling "animal-like noises" at the scene and later gave investigators a false name, Sheriff Snyder said.

The sheriff's office said hospital officials suspected Harrouff may have ingested "caustic" chemicals from the couple's garage, based on what they were seeing in his body fluids.

The FBI is running tests to determine whether he was under the influence of synthetic drugs such as bath salts or flakka.

The gory details echo the Miami face-eater case, a random 2012 attack on a homeless man that made international headlines and spawned jokes about zombies.