COLOGNE, Germany (AP) _ The Israeli gunman walked down the aisle of the bus, asking the elderly tourists where they were from. When he came to the first German, he shot the 64-year-old woman three times, killing her.

Twenty minutes later, police stormed the bus and killed the gunman, 31-year-old Leon Bor, with a single shot to the head.

Bor had held police at bay for eight hours Friday just across the Rhine River from a historic cathedral. He had killed the driver 40 minutes into the $16, two-hour sight-seeing tour, and wounded a policeman and another tourist.

Police on Saturday said Bor appeared to be mentally disturbed. He took Polaroids of his victims and ordered passengers to photograph him posing in commando gear. He raved about the Russian mafia, last year's massacre in a Hebron mosque, and a trip to Paris.

But despite the slaying of the German woman, police weren't sure Bor was anti-German and didn't know what motivated him to commandeer the bus as it pulled up by the river to let the 24 tourists, mostly elderly Germans, Austrians and Americans, get out and snap pictures.

Born Leonid Borschevsky in Russia, Bor moved to Israel in 1989 and became a citizen. He had been living in the United States for the last two years, police said. They would not say in what city.

On Friday, he carried a 9-mm Smith and Weston pistol, a sextant _ used to navigate at sea _ a parachute and a black commando uniform, which he donned after shooting the bus driver.

``This was a killer who would stop at nothing,'' said prosecutor Karl Uterman. ``He was an absolute sadist who killed for the fun of it.''

Yet he acted cooly, firing his pistol professionally and holding police back by fooling them into thinking that sticks of silver-painted wood strapped to his chest were dynamite.

Two hours into the standoff, Bor called the police emergency line from the bus' portable phone and demanded a Russian interpreter. In the meantime, three passengers escaped, including a woman who left behind her sons, ages 11 and 12.

The youngest boy later jumped out the broken back window of the bus. As the gunman fired at him, Heinz Buchner, a 53-year-old Austrian passenger, threw himself in the line of fire and was hit in the upper chest.

About two hours later, Buchner also jumped out the back. He was badly wounded but out of danger Saturday.

``Although this was a tragedy, there was a hero,'' said police commander Winrich Granitzka. Buchner ``risked his life and paid with terrible injuries.''

Shortly after Buchner escaped, Bor asked the nationalities of the passengers. When a woman told him she was German, he shot her three times in the neck and head. She died instantly.

Police heard the shots and decided they had to move fast. Twenty minutes later, they fooled Bor into thinking officers were approaching to give him a cellular phone, then stormed the bus and killed him.

Along with the driver, there were 11 Germans, four Americans, four Austrians and two Japanese on the bus, as well as an Argentinean, a Turk and an Israeli. As is German practice, police did not identify them further.