A security guard may have contaminated Miss Puerto Rico Universe's clothes and makeup brush with pepper spray.
Police are also reviewing a video showing the same guard kissing a rival beauty contestant, according to police chief Pedro Toledo, who said it is part of investigation into whether the discharge of pepper spray was an accident.
Contest winner Ingrid Marie Rivera, 24, shocked the U.S. Caribbean territory last month with allegations that something caused her face to swell and break out in hives between her appearances on stage. Pageant director Magali Febles said she believes there was a conspiracy to sabotage Rivera's bid.
Witnesses have told police that the pepper spray was released backstage "while someone was apparently playing around," said Toledo, who did not elaborate.
After Rivera's evening gown and makeup brush tested negative for pepper spray last week, pageant officials submitted new evidence, including a swimsuit that they say she wore during the pageant.
Authorities are investigating whether the suit may have been doused with pepper spray after the accusations were made public, Toledo said.
If Rivera's swimsuit and other items test negative for chemicals, police might give polygraph tests to attendees and pageant organizers who talked to the media, police spokesman Lt. Eddie Hernandez said.
Rivera was composed while strutting before judges at the pageant in San Juan on Nov. 23, but once backstage, she stripped off her clothes and applied ice bags to her face and body.
Her allegations of beauty pageant backstabbing have attracted worldwide media attention. Rivera recently flew to the U.S. mainland for a round of high-profile TV appearances, including one on "The Ellen DeGeneres Show."