The FBI analysis of blood from Austin Harrouff, the suspect in the cannibal-style attack and killings near Tequesta shows no evidence of him being under the influence of Flakka or bath salts, according to a statement from his attorney.
The tests have been at the center of the investigation into the double murders.
Harrouff is accused of killing John Stevens and Michelle Mischon at their home last August.
The first deputy on scene found Harrouff biting the face of Stevens.
Investigators wanted to find out if Harrouff was on any drugs at the time of the attack.
Harrouff has been charged with two counts of first-degree murder and one count of attempted murder for attacking a neighbor who tried to intervene.