On a weekend marred by violence across Israel, a 23-year-old Jaffa man was shot dead by unknown assailants on the city's Rehov Bikurei Zion Friday night. Two other young men of the same age were moderately and lightly wounded in the incident. Police said that the shooting was criminally motivated. No arrests have yet been made. In other violence, a 40-year-old Hadera woman was arrested Saturday after threatening to murder her five-year-old son in front of police officers. Police were called to the woman's apartment following reports of shouting. When they entered, the mother pulled out a knife and threatened the boy. Police disarmed the woman and she was sent for a psychological examination. Meanwhile, two Nazareth men were arrested on suspicion of shooting their brother and lightly wounding him in the leg. The reason cited for the shooting was an argument between the men's sons. A third man was also arrested on suspicion of involvement in the incident. Early Saturday morning, a 17-year-old was arrested on suspicion of attempting to rape a 22-year-old woman in Upper Nazareth. The teen allegedly waited for the woman at the entrance of her building, followed her into the elevator and threatened her at knifepoint. The woman persuaded her attacker to enter the apartment with her and she then screamed, waking up her flatmates. The teen fled but was soon arrested along with a 20-year-old suspected accomplice. In yet another violent incident, a security guard at a pub in Haifa was lightly wounded Saturday when he was stabbed by a man whom he had ejected from the premises. The guard said the man was drunk and was causing a disturbance. The assailant fled the scene. On Friday night, a policeman was lightly wounded when he was stabbed in the neck with a broken bottle near a Tel Aviv nightclub. The incident occurred when police officers tried to break up brawlers in the city's Rehov Hamasger. In addition, a 38-year-old Jerusalem man was seriously wounded Friday night when he was stabbed on Tel Aviv's Rehov Hatzfira. Police opened an investigation into the incident. Elsewhere, two young men were moderately Friday night and seriously wounded, respectively, when they were stabbed during a fight in Rishon Lezion. The two were evacuated to Tel Hashomer's Sheba Medical Center and Assaf Harofeh Hospital. Police said that a fight broke out between two groups of men in their 20s outside a cluster of nightclubs in the city.