A naked man described as having "superhuman" strength sent three people to the hospital in a wild attack near Delray Beach in the US state of Florida, including one person who was bitten on the face, police said.
Two of the injured people - a retired New York police officer and an 18-year-old youth who suffered the bite and fought his attacker with a box cutter - were badly beaten, according to Palm Beach sheriff's office spokeswoman Teri Barbera.
The third, a 10-year-old boy, was hurt while trying to scramble under a gate to escape. The names of the victims have not been released.
Their unidentified attacker, who officials say appeared to be in a "state of psychosis" and fought off police on Tuesday, died at the hospital after being shot three times by an officer, who has not been named.
Barbera said the man, described as being about 185cm tall and weighing about 115kg, flailed and tried to get up after the gunshots hit him in the torso and lower body.
He continued fighting when paramedics arrived and tried to treat him, but was finally subdued and taken to hospital.
Palm Beach sheriff Ric Bradshaw on Tuesday said it was not clear whether the man died from the gunshots, a chemical substance or something else. On Wednesday, the office was still trying to identify him and notify relatives.
The incident began when the naked man badly beat the retired officer and then ran off. He then attacked the 18-year-old, beating him and biting his face, Barbera said.
That was when the teen grabbed a box cutter and tried to defend himself. After that, the attacker chased after a man and his 10-year-old son, who hurt himself while trying to get away.
Arriving police officers used a Taser stun gun, but said it had no effect on the man. That was when one of the officers shot him, Barbera said adding that the officers' actions "probably stopped a lot of other people from getting hurt really bad tonight".