Documents released in UK tourist killings in Fla.

Anonymous tips led investigators to a suspect in the shooting deaths of two British tourists, and authorities found the same caliber of bullets used to kill the pair in the suspect's room, according to Sarasota County court documents released Tuesday.

Shawn Tyson, 16, has been charged as an adult with first-degree murder in the April 16 shootings of James Kouzaris, 24, and James Cooper, 25. Police are still trying to figure out why the British men were in a housing project, where they were killed, after a night of drinking in Sarasota bars.

The documents that detailed some of the evidence against Tyson had been sealed since his arrest. According to the documents, Tyson was arrested and charged April 7 with aggravated assault with a firearm in an unrelated case. Authorities claimed he fired into an occupied car during a dispute, but Tyson said he only fired a revolver into the air.

When officers searched his bedroom, they found two .22 caliber bullets, the same caliber police said were used to kill Kouzaris and Cooper. Following several anonymous tips, a new search of Tyson's home found a black ski mask and another .22 round.

Tyson had been released from juvenile detention April 15, a day before the killings.

Court records show authorities are still looking for a second possible suspect. One witness told investigators that two white males matching the descriptions of Kouzaris and Cooper were being chased by two black males. After several shots were fired, witnesses reported two black males running away from where the victims' bodies were found.

No one answered the telephone after hours at the public defender's office. Tyson is being held without bail.