A security guard who hit three colleagues over the head with a crowbar before jumping off a footbridge was jailed for three years and eight months yesterday. Lau Yuk-sing, 56, had earlier pleaded guilty to three counts of wounding with intent to do grievous bodily harm by attacking his colleagues in the early morning of August 6 last year. He struck Fung Kam-choi, 46, Lau Wing-kei, 57, and Mak Yuen-kwan, 58. The four had been involved in a dispute at the Cheung Sha Wan estate where Lau Yuk-sing worked. Lau alerted police after the attacks before jumping off the bridge. He is now permanently disabled. District Court Judge Stephen Geiser said Lau's actions had been unprovoked and were 'wicked attacks'.