Investigators suspect that the spring breaker removed her clothing, leaving it on the lounge chair, before entering the ocean and drowning while wearing a brown bikini.

The last person to see University of Pittsburgh student Sudiksha Konanki before she vanished had his passport seized by authorities in the Dominican Republic, according to a new report. Officials on the Caribbean island confiscated Joshua Riibe’s travel documents nearly 10 days after Konanki was last seen with the 22-year-old Minnesota college senior on the beach near their RIU Hotel & Resort on March 6.

St. Cloud State senior Joshua Riibe has remained in his hotel room under police surveillance when not questioned at the police station, his parents said.