Israeli forces have detained five Palestinians after an Israeli man was beaten to death at his home in the occupied West Bank.
Sraya Ofer, a retired colonel, was killed after going to investigate noises coming from his garden in the northern Jordan Valley, police say.
His wife was injured but escaped and raise the alarm. Checkpoints were set up as security forces scoured the area.
Israeli media say the couple had been attacked with iron bars and axes.
Israel Defence Forces (IDF) spokesman Peter Lerner said the Palestinians had been detained in an investigation "focused on intelligence".
The attack took place at around 01:00 (22:00 GMT) at Brosh Habiqa resort, part of the West Bank settlement of Shadmot Mehola.
The woman, who escaped through a security fence, told police the attackers were Palestinians.
The incident happened in a part of the Jordan Valley which Israel captured in the war of 1967 where the construction of Israeli homes and businesses is widely considered a breach of international law - something Israel does not accept, says the BBC's Kevin Connolly in Jerusalem.
The dead man is the third Israeli to be killed in what Israel characterises as "terror attacks" in the last month in the West Bank. Two serving soldiers have also died.
Israel security officials quoted in the local media have not appeared to detect a pattern in the sudden increase in the level of violence, but at least one right-wing member of the cabinet has said Israel should respond by ending peace talks with the Palestinians, our correspondent adds.