Israeli police were on high alert after special forces shot dead an American-Israeli prisoner, who opened fire on prison guards.
Inside this jail near Tel Aviv, Samuel Sheinbein shot three security officers, critically injuring one, and barricaded himself in the compound.
The prison authorities said it was not clear how he came by the weapon.
"This is our assessment -- it was an old gun, we believe this pistol was brought in from the outside. In the prison authority there are no guns, the guns are only in secure places, so there is no way he could have got hold of a gun through us. What we believe is that the gun was brought in and the way it was brought in must be investigated, so a senior team has been named to investigate how a gun got into an Israeli prison."
Sheinbein was serving a 24 year sentence in Tel Aviv for a brutal murder he committed in the US in 1997.
He fled to Israel shortly after the killing, in a case that briefly soured US-Israeli relations.
Israel's refusal to extradite the teenager to the US - where he would have faced a harsher penalty - outraged US authorities.
It led to a change in Israel's extradition laws.
American-Israeli prisoner killed in jail battle with police (1:22)
Feb. 24 - Israeli police clash with American-Israeli prisoner and kill him in jail battle. Sarah Toms reports. ( Transcript )