JERUSALEM -- A Palestinian man lured an Israeli soldier he worked with at a sandwich shop outside Tel Aviv to the West Bank on Friday, and killed him in hopes of using the body as leverage to lobby for the release of his brother from an Israeli prison, military officials said Saturday.
Lt. Col. Peter Lerner, a spokesman for the Israeli military, said the Palestinian, Nidal Omar, confessed to the crime after being arrested early Saturday along with seven others.
The closeness of the relationship between Mr. Omar, 42, and the 20-year-old soldier, Sgt. Tomer Hazan, remained unclear late Saturday, but the owner of the shop in Bat Yam where they worked said in a television interview that both men were well liked. Colonel Lerner said Mr. Omar had persuaded Mr. Hazan to go with him in a taxi Friday from Israel to a Jewish settlement in the West Bank and then to Beit Amin, a nearby Palestinian village of 1,100 where his family is from.
Mr. Omar then took Sergeant Hazan to an open area, killed him, and hid his body in a water cistern, according to Colonel Lerner, who said Mr. Omar "wanted to barter with the dead body." Colonel Lerner did not say how the soldier had died.
The news heightened tensions even as the Palestinians and Israelis have entered peace talks.
Mr. Omar's relatives said he is married to an Israeli citizen, lives in the Arab-Israeli town of Jaljulia with her and their eight children, and had earned about $2,500 a month serving shwarma in the Bat Yam shop for the past four years. But Colonel Lerner said Mr. Omar did not have the permit required to work or stay in Israel.
On Saturday night, several hundred people protested outside the sandwich shop against Palestinians working illegally in Israel, some of them shouting, "Death to Arabs."
Since the second intifada a decade ago and Israel's subsequent building of a barrier separating it from most of the West Bank, Israeli travel into Palestinian villages is relatively uncommon. Colonel Lerner said the authorities are investigating how Mr. Omar persuaded Mr. Hazan to go with him.
The kidnapping of soldiers in Israel, where military service is mandatory for most Jews, is among the most profound fears for Israelis. In late 2011, Israel agreed to release more than 1,000 Palestinian prisoners in exchange for Gilad Shalit, a soldier who had been abducted five years before by Hamas militants from the Gaza Strip.
The Israeli military recently reported a sharp rise in Palestinian plots to kidnap soldiers in hopes of trading them for some of the 4,500 Palestinian prisoners in Israeli jails. A total of 37 such plans have been thwarted so far this year, more than in all of 2012, according to Colonel Lerner.
Israel released 26 long-serving Palestinian prisoners last month, and is expected to release about 75 more in three phases, as part of the Washington-brokered peace talks that started this summer. Right-wing politicians who oppose the establishment of a Palestinian state seized on the killing to bolster their argument.
"One does not make peace with terrorists who throw soldiers' bodies into a hole in the ground," Naftali Bennett, an Israeli minister, said Saturday. "One fights them without mercy."
Colonel Lerner said that Mr. Omar's imprisoned brother, Nur ad-Din Omar, had been incarcerated since 2003 and was a member of the Tanzim militia, an offshoot of the Fatah faction.
Another brother, Mahmoud Abdullah Omar, said he was serving a 30-year sentence for a shooting that injured some Israel soldiers.
Sergeant Hazan was in a noncombat job in the Air Force and worked part time at the sandwich shop. His Facebook page, filled Saturday with condolences, showed photos of him at parties and pools.
"He was like my son, there's no other boy like him," the restaurant owner said on Israel's Channel 2 news. Of Mr. Omar, the owner -- who was not identified -- said: "He was on good terms with everyone. Nice as can be."
The military said Mr. Hazan's family reported him missing at 10 p.m. Friday, prompting an investigation. Mr. Omar's mother said many Israeli soldiers with three dogs arrived at 3 a.m. Saturday, and stayed until 4 p.m. Six Omar brothers were arrested, she said.
"I condemn what he did a million times," said Mahmoud Omar, who was not among those arrested. "He ruined our lives."
Said Ghazali reported from Beit Amin, West Bank, and Carol Sutherland and Irit Pazner Garshowitz from Jerusalem.
This article originally appeared in The New York Times.