Was Tel Aviv gunman driven by ISIS or emotionally unstable?

Sami Melhem, an Israeli Arab lawyer, said the shooter was a relative of his, whose father, a police volunteer, had come forward to identify him to authorities after the security footage aired.

Tel Aviv gunman moments before he starts shooting
The suspected gunman in the deadly shooting attack that killed two people and wounded seven others in Tel Aviv on Friday is emotionally unstable and not an adherent of Islamic State, a family attorney told Israeli television.
Sami Melhem, an Israeli Arab lawyer, said the shooter was a relative of his, whose father, a police volunteer, had come forward to identify him to authorities after the security footage aired. The 28-year-old suspect's name was withheld from publication under a court gag order.
Speaking to Channel 2, Melhem said he had previously represented the suspect in a case where he was jailed for assaulting an Israeli soldier. But Melhem described him as mentally unstable rather than politically militant.
Video of Tel Aviv shooting
"This man is not sane, to the best of my knowledge since I represented him," Melhem said. "He has received treatment. He is receiving treatment. Recently he has been going around in the street as an insane person."
Asked if the suspect had radical religious tendencies, Melhem said: "I do not know."
Israeli security officials are increasingly convinced that the shooting was motivated by nationalist sentiment.
Four wounded in shooting on Dizengoff street, Tel Aviv, January 1, 2016.
The suspected gunman is known to Israeli security forces since he had been arrested and sent to prison for attempting to steal an IDF soldier's gun.
Authorities continue to hunt the suspected gunman, a native of the Israeli Arab village of Arara. Those from the Wadi Ara community who know the gunman told Israeli media that the individual "experienced a number of traumatic events in his life."