Police arrested an 18-year-old man who allegedly attacked another man without provocation in a Kalihi park. 

Police said an 18-year-old man was hanging out at the park with friends about 3:30 p.m. Wednesday when the attacker came up with two other males and attacked the first group. 

The assailant hit the victim with a blunt object, causing injury, police said. 

The victim escaped and reported the attack. Police found the attacker, who gave a Kalihi address, and arrested him on suspicion of second-degree assault.