The world's most famous houseboat -- where Andrew Cunanan, the killer of fashion designer Gianni Versace, committed suicide in July -- sank today.

The blue two-story houseboat, which has become a macabre tourist attraction, listed at its rear and settled on the bottom of Indian Creek, a Miami Beach waterway, after developing a problem with its bilge pump.

At the front, most of the boat remained above water while the back was immersed up to the second story.

"It has been taking on water since this morning," said Miami Beach police spokesman Al Boza. "It is not a police matter."

Images of the craft flashed around the world when police besieged and then stormed it July 23 after receiving a tip from the houseboat's caretaker about an armed man inside.

Cunanan shot himself in the head on the upper floor, either when police fired tear gas into the houseboat prior to storming it, or earlier when Portuguese caretaker Fernando Carreira stumbled upon him.

Cunanan, a gregarious socialite and gay gigolo, had murdered four men, including a former lover, in a cross-country killing spree before shooting Versace to death on July 15 outside the designer's Miami Beach mansion.

The houseboat's owner, a German citizen named Torsten Reineck, was arrested in Frankfurt in August on fraud and tax charges unrelated to the Cunanan case.

Local television said today that Carreira telephoned Reineck to inform him of the sinking. Miami Beach officials said Reineck would face fines and could be required to remove the houseboat from the waterway if it is not refloated.

Carreira collected thousands of dollars in rewards for information leading police to Cunanan, who was on the FBI's list of 10 most-wanted fugitives even before he shot Versace.

He now drives a Mercedes and promotes a pistol holster called the "Caretaker Quick-Draw" -- he had trouble drawing his gun when he stumbled on Cunanan -- but still takes care of the houseboat.

Police have so far been unable to account for Cunanan's movements between the slaying of Versace and his suicide nine days later just two miles away from Versace's villa. A definite link between Cunanan and Reineck has not been established..

Police files on the Versace slaying will be released at the end of the year. The Miami Herald reported Saturday that the Versace family is asking that some sensitive information contained in the files be withheld.