This undated photo provided by the Israeli Police shows a handmade gun produced in the West Bank. Welded together from spare gun parts and pipes, the gun looks like a handgun but with an extended barrel and a long magazine of bullets. The weapon, known by its street name "Carlo," was used by Palestinian gunmen to kill four people and wound five others in Tel Aviv on Wednesday night as well as several other attacks since the current round of violence erupted in September. (Israeli Police via AP)