(CNN) -- The man suspected of trying to attack the Dutch royal family by crashing his car near their bus has died, Dutch police said Friday.
A car is pictured after crashing into the crowd waiting for the visit of the royal family in Apeldoorn.
The man, whose name was not released, had been seriously injured in the crash Thursday in the town of Apeldoorn, about 45 miles east of Amsterdam, police said. He died early Friday, police said.
He had been charged with trying to attack the royal family, authorities said. Were you there? Send us your video, images
Police searched the man's house but found no weapons, explosives, "or any other clues that could lead to the involvement of other people," police said.
Five people, as well as the driver, were killed and 12 were wounded in the incident, which happened during the country's annual Queen's Day celebration, police said.
Crowds had lined the streets to see Queen Beatrix and her family ride by in an open-top bus during the Netherlands' annual holiday. See who the Dutch royal family are »
As the bus moved along, a black hatchback zoomed past it. The crowds were behind barriers off the road, but security officials and journalists, including many cameramen, were in the road as the car went by.
The car crashed into the low metal railing around a column on the side of the road. The vehicle appeared heavily damaged even before the crash, but the reason for that was unclear.
There was no one other than the driver in the car at the time, police spokeswoman Esther Naber said.
Members of the royal family saw the crash and gasped, then quickly sat down as the bus continued driving.
The attack caused outrage in the Netherlands, newspapers Friday widely expressing disbelief and suggesting the monarchy would have to change.
"Queens Day will never be the same," the Trouw newspaper said. "The Netherlands always has been proud of their no nonsense royal family. With this comes a Queen who not only cycles a bike, but also mixes with people without obvious security measurements. Is that still possible now the royal family has been the target of an attack?"
The Algemeen Dagblad newspaper agreed.
""What is going to happen on the 30th of April next year? And will we continue to see the members of the royal family cycling through the canals of Amsterdam or hunting for bargains in the Bijenkorf in The Hague?"
Queen's Day is a national holiday in the Netherlands, the Netherlands Antilles, and Aruba. The tradition started in 1885 and celebrates the birthday of the queen.
Although Queen Beatrix's birthday is January 31, she officially celebrates her birthday April 30, according to the Dutch government.
Queen's Day is known for its free market all over the country, where anybody is allowed to sell things in the streets. Other activities include children's games and musical performances.
The day is marked with the color orange all over the country as a reference to the colors of the royal family, who come from the House of Orange-Nassau.
Emmy Dexel contributed to this report.