The search intensified Tuesday for missing US citizen Aaron Sofer, last seen Friday in Jerusalem, with police saying they were investigating whether Sofer could be the victim of violence relating to the Israeli-Palestinian conflict.

Sofer, 23, who hails from Lakewood, New Jersey, was last seen on Friday at midday. He is known to have been on a hike in the Jerusalem Forest with a friend, and at some point Sofer went down a slope by himself and since then there has been no trace of him.

Police spokesman Micky Rosenfeld said Tuesday that police have launched an extensive search for Sofer, who is an ultra-Orthodox student at a yeshiva in Jerusalem.

Rosenfeld said police are pursuing all avenues in their investigation, including “nationalistic motives,” a phrase related to the conflict between Israel and Palestinian terrorists.

In June, three Israeli teenagers were abducted and killed in the West Bank by Palestinian terrorists and, following the discovery of their bodies, a Palestinian teen was kidnapped and killed in the Jerusalem Forest by Jewish terrorists.

A spokesperson for the Sofer family, Dov Hirth, told The Times of Israel that the FBI was also involved in the matter and that the US embassy in Israel was “fully aware” of developments.

Police helicopters began searching for Sofer on Friday night and by Saturday night increasingly large search parties combed the forest for the missing student.

Police also hung pictures of Sofer in synagogues in the Har Nof neighborhood, which abuts the Jerusalem Forest close to where he disappeared. The large local ultra-Orthodox community has been galvanized into action, taking part in searches and organizing additional sweeps of the area.

Sofer’s disappearance has been particularly baffling because from any point in the Jerusalem Forest it is little more than an hour’s walk to built-up areas, police said.

On Monday, New Jersey politicians called for more help from both the US and Israeli governments in the search for Sofer. US Rep. Chris Smith and other local officials in New Jersey were planning a news conference for Tuesday in Lakewood to seek help in finding the student.

Sofer’s parents have flown to Israel, and concern for his safety has risen within the US Jewish community. A neighbor told CBS New York on Monday that “It’s scary to think what possibly could be the ramifications… [a] great fear is that he was accosted; he was taken away, kidnapped.”

Aaron Sofer

Aaron Sofer

Sofer is described by police as 1.75 meters tall, with a short red beard, glasses, black pants, a white shirt and a black skullcap.

Dozens of volunteers who began searching for Sofer on Saturday night renewed their efforts in greater numbers the following morning.

Search and rescue units and a police canine unit also joined the hunt, which is focused on the Jerusalem Forest area to the west of the capital.

Search parties have scoured the forest as well as the Bayit Vegan, Hadassah, and Ein Kerem neighborhoods, all of which overlook parts of the forest.

Police asked that anyone with information that might be helpful in locating the missing student call 02-539-1520.

The Associated Press contributed to this report.