A woman was arrested in Kwun Tong last night, 91/2 hours after she went berserk on the streets of Hung Hom, attacking four pedestrians with a plastic broom and a mop handle and vandalising two shops. The woman, 40 and surnamed Lam, was described as laughing wildly during the morning rampage. She escaped before police arrived. Police made the arrest at a flat in Hang On House, Wo Lok Estate. Officers are investigating whether she has mental problems. She was being held in custody. Lam's rampage began at about 9am when she used a broom to beat the head of a female newsstand vendor, 77 and surnamed Liu, in To Kwa Wan Road near the junction with Chi Kiang Street. Carrying the broom, she was later seen chasing a man in Wing Kwong Street, about 200 metres from the newsstand, according to police. A police officer said she apparently failed to catch the man and then hit a female cleaner, 59, surnamed Heng, on the leg. A female passer-by, 54, surnamed Chan, approached to mediate and was beaten on the arm. She was bandaged at the scene. 'After the attack, she laughed wildly while fleeing on foot,' a witness said. Minutes later, the attacker appeared in To Kwa Wan Road near the junction with Kwei Chow Street, about 400 metres from the site of the second attack. This time she carried the wooden handle of a mop, police said. She grabbed bags of Chinese herbs from the entrance of a pharmacy and tossed them on the pavement before running into a herbal tea shop, where she knocked over bottles of tea. The woman ran out of the shop and attacked her last victim - a salesman, 51, called Lau - as he emerged from a fast-food restaurant. She then dropped the pole and fled. '[The wooden pole] is thick and about 1.5 metres long,' Mr Lau said at Queen Elizabeth Hospital. 'She kept beating me. She hit me seven or eight times.' When asked why he did not stop her, he said: 'She is a woman. I could not have contact with her.' Ms Liu and Ms Heng were discharged from Queen Elizabeth Hospital. A police officer said: 'We were told that she laughed and screamed loudly after each attack.' Police believed the attacker picked up the broom and the mop handle in the street. Detectives from Kowloon City police station are investigating.