FBI test results showed no evidence that Austin Harrouff had either bath salts or flakka in his system when authorities found him biting a dead man's face after killing two people in their Martin County, Florida, home, according to one of his attorneys, Nellie King.

King said in a prepared statement that Harrouff had several drugs in his system that were "medically introduced to him" at St. Mary’s Medical Center, where he went for treatment of his injuries. They also found minimal levels of THC, the active ingredient in marijuana.

The FBI's drug lab in Quantico, Virginia, also found ethanol, or alcohol, in Harrouff, but its source was not identified. It could have come from swallowing chemicals in the garage at the home where the attack took place, King said.

King said Harrouff "is struggling with severe mental illness, and the judicial process will bear all of this out in due time."

Harrouff, 19, and his attorneys pleaded not guilty to two counts of first-degree murder, attempted first-degree murder and burglary last week. Authorities said Harrouff stabbed John Stevens III, 59, and Michelle Mishcon, 53, to death at their home on Aug. 15.

The Federal Bureau of Investigation was asked to do a more thorough test for designer drugs such as flakka and bath salts, soon after the attacks.

When Harrouff was taken to St. Mary's Medical Center after they were able to separate him from Stevens' body, deputies said Harrouff told them he ate something bad. When they asked what, Harrouff replied, "Humans."

The Florida State University student remained in the hospital for weeks until he was arrested Oct. 3 by Martin County sheriff's deputies.

Initial drug tests checking for common drugs, like cocaine, marijuana and heroin, came back clear, according to the sheriff's office. Though he told deputies on the scene he had no drugs in his system and to "test him," court documents showed he told paramedics that he smoked marijuana and had alcohol.