A bombing suspect who is accused of blowing up a hotel toilet in Copenhagen, along with himself, is a one-legged amateur boxer who was born in insurgency-racked Chechnya and has shown what one scholar calls "highly professional" tradecraft in concealing his identity and purpose from Danish authorities.

The would-be bomber's target, Danish police said, was likely the Jyllands-Posten newspaper, which sparked outrage throughout the Muslim world in 2006 by publishing 12 cartoons depicting the Prophet Muhammad and has been the object of at least one foiled terrorist attack since.

"We are reasonably sure that was the target," Chief Superintendent Svend Foldager of the Copenhagen police, the lead investigator in the case, said at a briefing Friday.

"We're dealing with a letter bomb," said Mr. Foldager, adding that the parcel contained small steel pellets designed to maximize casualties and would have exploded with a force of a small hand grenade. "It was capable of injuring a lot of people, depending on where it exploded."

Mr. Foldager also said the device used triacetone triperoxide, or TATP, a volatile acetone-based explosive used by al Qaeda in the July 2005 London subway bombings and other attacks.