Authorities in Berlin said Sven Jaschan released the newer worm, Sasser.e, just before his arrest on Friday in Waffensen, Germany. But experts are speculating the involvement of group of developers, who might have released the worm after Jaschan's arrest.
Jaschan, who was arrested after a tip-off through Microsoft's reward scheme, admitted he wrote the worm. Four variants of the worm have emerged so far, all purporting to be from the same source. Police also said Jaschan was responsible for the Netsky worm.
Jaschan, who recently graduated from school, could face damage claims from victims of the worm and a five-year sentence for computer sabotage.
Prosecutors said Jaschan could have written the worm to help his mother's business, a small computer helpdesk company.
Police released Jaschan without bail.