The man who drove his car into a crowd of parade spectators and killed five in an attempt to attack the Dutch royal family died early Friday of his injuries, prosecutors said. The 38-year-old suspect, identified by Dutch media as Karst Tates, had been in critical condition since the attack that marred the Netherlands' Queen's Day holiday on Thursday. Twelve other people were hurt when Tates rammed his car through police barricades toward an open-topped bus carrying Queen Beatrix and several other members of the royal family. Tates told one of the first police officers to rush to his car that the attack was aimed at the royal family, prosecutor Ludo Goossens said Thursday. But the motive was unclear. Prosecutors said Tates' death ended the criminal investigation against him, but that they would continue to investigate whether he acted alone. Prosecutors have not released his identity, in line with Dutch privacy laws. "So far there are no indications" anybody else was involved, prosecutors said in a statement. Police who searched Tates' house Thursday "found no weapons, explosives or indications of other suspects," prosecutors said. Tates' failed attack on the immensely popular royal family played out live on nationwide television during coverage of the queen's bus trip to her palace Het Loo in the eastern city of Apeldoorn. Friday newspapers and Web sites featured photos of the carnage wreaked by his small black car as it plowed through crowds of people hoping to catch a glimpse of the royals. The car came to a halt when it slammed into a stone monument just meters (yards) from the royal bus. A shaken Queen Beatrix extended her sympathies to the victims in a brief nationally televised address Thursday. "What began as a great day has ended in a terrible tragedy that has shocked us all deeply," she said. Tates was charged with attacking the royal family, manslaughter or murder and had faced up to life imprisonment if convicted. Dutch media, citing neighbors, said he recently was fired from his job and was to be evicted from his home. Police said he had no history of mental illness or police record. Officials in Apeldoorn said he had a map of the queen's route. Celebrations were canceled for Queen's Day, the national holiday that draws millions of people to street dances, picnics and outdoor parties around the country. Flags were lowered to half staff.