Alpha-PVP, a powerful stimulant nicknamed Flakka, is shown after being seized by Broward County police in this image released, May 28, 2015. REUTERS/Broward Sheriff's Office/Handout

A 19-year-old man who was accused of stabbing a Florida couple to death before trying to eat their faces and maiming a third person was charged with first-degree murder Monday, according to reports. Karen Mischon, 53, and her husband, Joseph Steven III, 59, were found dead in their driveway in late August after being attacked by Florida State University student Austin Harrouff. Police were responding to a call made by Harrouff’s third victim, Jeff Fisher, who had also been stabbed three times in the back after attempting to stop the attack.

Fisher stumbled upon Harrouff eating parts of Steven’s face and stomach when he called the police. When authorities arrived at the scene, they found Harrouff on one of the alleged victims and said it took several officers and a K-9 to pry him off. Harrouff was said to be “abnormally strong” and was unaffected by a Taser authorities initially used to get him off of the victim. Fisher was airlifted to an area hospital where he was treated and released several days later.

Following the attack, Harrouff was in and out of consciousness and was unable to answer any questions regarding the incident. However, authorities say they have enough evidence against the student, which has led to his arrest and charges of two counts of first-degree murder and one count of attempted murder. Harrouff has no bond option at this time.

On the day of the attack, Harrouf’s parents had called the police and his university's Alpha Delta Phi fraternity brothers to help find him after he abruptly stormed out of a restaurant he had been dining at with his family. Reports say he may have walked about three miles to Jupiter, Florida, where his victims resided.

Although the young man tested negative for all common drugs, authorities believe he may have been under the influence of flakka – a strong hallucinogen form of bath salts sometimes called the zombie drug that has also been connected to other face-biting murders. Harrouf’s toxicology test has been sent to a lab in Quantico, Virginia, where researchers will be able to determine whether or not he was under the influence of flakka or something else.

Harrouff could face the death penalty if convicted.