Christos Kendiras, 48, broke a window and jumped from the seventh floor of the police headquarters building in downtown Athens after police had finished taking his fingerprints, authorities said. He died instantly.
Public Order Minister Mihalis Chrisohoidis ordered "an immediate investigation to determine how this occurred," said Dimitris Efstathiadis, general secretary of the public order ministry. "The minister wants to find out in zero time what happened, to find out what the conditions were that led to him jumping."
Two police officers had been escorting him when he broke free from them and ran at a window, authorities said. He landed on a second-floor balcony, they added.
"Unfortunately, we had this event, which is not the best thing that could have happened to us," Efstathiadis said. "There is no justification after the drama we had yesterday for any relaxing of security measures and to have this happen."
Kendiras had been due to appear before a public prosecutor in the port of Piraeus where he worked in order to be formally charged at around 11:30 am (0930 GMT). Fingerprinting was one of the last procedures he had to go through before being taken to the prosecutor in court.
On Saturday, Kendiras had hijacked a bus with 35 people, including 33 Japanese tourists, after killing his mother-in-law and a friend in southern Greece over a family dispute.
In a deal arranged with police late Saturday to end the hostage drama, he surrendered to popular television show host Makis Triantafilopoulos after holding the tourists hostage for nearly 10 hours. None of the tourists, who had been on a three-day visit to the Peloponnese, were harmed.
An executive for the Japanese tour operator, Hankyu Express, said in Tokyo that the company was arranging for a psychiatrist to fly in from Paris for them.
Triantafilopoulos said that in their conversations during the hijacking, Kendiras had said he wanted to kill himself and had placed the shotgun he was armed with in his mouth.
He was transported to police headquarters from the TV station's studios after speaking to Triantafilopoulos about his problems.
Distraught because he believed his wife was cheating on him, authorities said Kendiras used a shotgun shortly after daybreak Saturday to kill 77-year-old Georgia Spyrou, his mother-in-law, and Stamatis Taktikos, 44, whom he suspected of being his wife's lover, in the village of Galata, about 125 miles southwest of Athens by road.
The auto body repairman then drove north to Epidauros, the site of a 4th century B.C. theater that is one of Greece's prime tourist attractions.
There, he set fire to his car and used the blazing wreck and gun to pull over a bus of Japanese tourists who were heading to the theater.
Threatening to kill his hostages, Kendiras took the bus on an all-day trip Saturday back and forth along the main highway connecting central and southern Greece. He demanded he talk to Triantafilopoulos, who began following the bus in a car.
Police chief Yannis Georgakopoulos said authorities concluded Triantafilopoulos was the best solution for an end to the crisis.
During the hijacking, Kendiras shot at police vehicles, slightly injuring one officer. Dozens of police cars, helicopters and ambulances followed the bus until Kendiras released the hostages and surrendered.
Police said he frequently threatened the passengers _ 23 men and 10 women, including a Japanese tour guide.
Greek police, having learned from two similar bus hijackings in one year, quickly isolated the vehicle from media and all other traffic once the standoff began. They flew in hostage negotiators and psychiatrists.
The government was concerned the hostage crisis might damage Greece's tourism industry in the run-up to the 2004 Olympics, and ordered police to make sure none of the Japanese were injured.
In conversations with the Alpha channel, where Triantafilopoulos works, Kendiras kept calling himself "the strange one."
"He wanted his demands to be heard," Triantafilopoulos said, but did not say what they were. "He said he wanted to kill himself. He said everything a hurt and bitter person can say."
He agreed to surrender at Triantafilopoulos' office in the Athens port of Piraeus. Triantafilopoulos had assured Kendiras his grievances would be aired if he gave up.
As he arrived, Kendiras gave his shotgun to bus driver Giorgos Tsakonas, bowed to the hostages _ who clapped _ and was escorted by officers and Triantafilopoulos to police headquarters.
Relatives say Kendiras was an angry man who grew even angrier when his wife, Marina, left him two years ago. Villagers in Galata claimed he had often been violent toward his wife and 22-year-old son.
(klei/AP)