The Latest on the killing of a couple by an attacker caught biting the dead man's face (all times local):

10:45 a.m.

Authorities say a 19-year-old Florida State University student accused of fatally stabbing a couple outside their home and then biting the dead man's face is now in stable condition.

Martin County sheriff's spokeswoman Trisha Kukuvka said in a text message Wednesday that Austin Harrouff will undergo hand surgery later in the day. Sheriff William Snyder had said Tuesday night that Harrouff's condition had deteriorated and he had been in danger of dying.

Snyder says Harrouff killed 53-year-old Michelle Mishcon and 59-year-old John Stevens in a random attack outside the couple's Tequesta home Monday night. Harrouff's attorney, Michelle Suskauer, did not immediately return a call and email seeking comment.

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7:45 a.m.

A 19-year-old Florida State University student charged with fatally stabbing a couple and biting the dead man's face remains under surveillance with guards by his side at a hospital.

Martin County Sheriff William Synder said Austin Harrouff was incoherent and making "animal-like noises" when he was taken to a hospital after the Monday night attack.

Snyder said Tuesday that Harrouff's condition was "life-threatening." West Palm Beach television station WPTV (http://bit.ly/2b0lqH8 ) reports Harrouff was sedated and on a ventilator Wednesday.

Snyder says Harrouff tested negative for a number of drugs, including methamphetamine. Results for substances known to cause excited delirium — such a flakka and bath salts — are pending. Synder noted that Harrouff didn't have the raised body temperature often associated with flakka use.

Authorities say 53-year-old Michelle Mishcon and 59-year-old John Stevens died and their neighbor was injured trying to fend off the attacker.