Police are investigating the ghoulish weekend incident involving 31-year-old Rudy Eugene, who was found naked and chewing on the face and neck of his victim on the off-ramp of a bridge in downtown Miami.
Police shot and killed Eugene when he failed to respond to orders to stop and back away.
The victim, identified by police as Ronald Poppo, a 65-year-old homeless man, is in critical condition at a Miami hospital.
Armando Aguilar, president of the Miami Fraternal Order of Police, said investigators were looking into whether drugs played a role in the attack.
"We've had at least two incidents in the past couple of months with people claiming they took a new form of LSD and complained of feeling a burning sensation that forced them to take their clothes off and led them to become very violent," he said.
He also said the drug could be a synthetic stimulant known as bath salts, which the Drug Enforcement Administration has linked to side effects ranging from an impaired perception of reality to agitation and delusional behavior.
Toxicology test results are not expected to be available for several weeks, Aguilar said. He described the attack on Poppo as "devastating."
"His mouth, his nose, and his ears were ripped off," Aguilar said. "What was left was the area around the goatee," he added.
"In my 30 years as a cop, I've never seen anything like this."