Neither he nor Arad could be reached for further comment.
Rabbi Yacov Borenstein, Hershkovitz's rabbi in New York, said Hershkovitz was eager to be in Israel to reconnect with his faith and study Judaism.
"It's terrible and shocking news," Borenstein told the Poughkeepsie Journal. "He was excited to go to Israel, but unfortunately it didn't turn out very well.
Oranim program participant Stas Abramovich, 27, said a number of people had complained about Hershkovitz to the program coordinator.
"There was something strange in his smile, but I never saw him as aggressive," Abramovich said.
Another participant, who spoke on condition of anonymity because he was afraid of repercussions from the program, said Hershkovitz had issued death threats to other members, but program coordinators ignored repeated complaints.
"He would talk to himself, share dreams that he'd had about random killings and mutilations that he did, he would have statements against Arabs or Nazis or terrorist type movements," the participant added.
Michal Bouaron, a guest at the hotel, told Channel 2 that police ordered guests to stay in their rooms during the incident. Later, police announced that it was safe for guests to leave their rooms.
"There was a lot of tension," Bouaron said. "Life goes on ... We won't let this ruin our day and our vacation."
The hotel was fully booked, Israeli media reported, because of the Jewish holiday of Sukkot, when many Israelis take vacations. Eilat, with attractive Red Sea beaches and hot, dry weather, is a favorite getaway spot.