The gunman, who was in his twenties or early thirties, fled after opening fire on the north shore of Lake Union and was being tracked by police using search dogs.
The shooting is the latest in a series of unexplained killings which have triggered an anxious cultural debate across the United States and prompted President Clinton to urge Congress to tighten gun controls.
The motive for Tuesday's killings in Hawaii was still unknown yesterday. Byran Uyesugi, who had worked for Xerox for 15 years, killed seven colleagues during an office meeting. He was arrested after a lengthy stand-off with police.
It has been just six weeks since a deranged loner in Fort Worth, Texas, stormed into a baptist church during an evening prayer service and opened fire, killing seven people before turning his gun on himself.
In June, a frustrated day-trader in Atlanta went on the rampage, killing 12 people in all, including his own family and customers at a brokerage firm.
Some of the attacks in recent months have been motivated by hate, including a white supremacist from Washington state who opened fire on a group of children at a Jewish community centre in Los Angeles before shooting a postman. Others have involved schoolchildren, notably the assault on Columbine High School in Colorado in April in which 15 people died.Reuse content