Missing University of Pittsburgh student Sudiksha Konanki’s clothes were found on the Dominican Republic beach where authorities believe she was last seen going for a swim, two police sources with knowledge of the investigation told ABC News on Monday.

The 20-year-old Konanki, a legal permanent U.S. resident and an Indian citizen, vanished early Thursday while she and a group of students were on a spring break trip to a resort in Punta Cana, according to the Loudoun County, Virginia, Sheriff’s office.

Konanki and one of her traveling companions were Loudoun County residents, the sheriff’s office said.

Konanki’s clothes were discovered on a portable beach bed close to the beach where she went missing, the sources told ABC News. Police have found no evidence of violence, according to the sources.

After going to a nightclub on Wednesday night, Konanki and a group of people went to the beach about 4 a.m. local time on Thursday, the sources said. The other women traveling with Konanki went back to their hotel about 5:55 a.m. and were captured on security camera returning to their rooms, the sources noted.

A man stayed behind with Konanki on the beach, according to a Dominican Republic investigative police report. The man, whose name was not released, told police that he and Konanki went for a swim and got caught by a big wave, the police report said.

The man, according to sources, told police that when he got back to the beach he threw up and went to sleep on a beach bed. When he woke up, Konanki was nowhere to be seen, the sources said.

Security video showed the man coming back to his hotel room at 9:55 a.m., according to the sources.

The man is not considered a suspect in Konanki’s death, the chief of the Civil Defense in the Dominican Republic told ABC News on Monday.

Right now, the investigation is being treated as an accident, the chief said.

Law enforcement authorities are increasing the perimeter of the search area of beaches and water in the ongoing operation to find Konanki, according to the chief.

Three Dominican officials involved in the investigation told ABC News over the weekend that Konanki is believed to have drowned in the ocean.

The last time Konanki was seen on the beach on security camera footage was around 4:15 a.m. Thursday, the Dominican Republic Public Ministry told ABC News.

The Public Ministry was first contacted by the U.S. embassy in the Dominican Republic on Friday, the Ministry said.

Officials said Konanki’s friends who were with her around the time of her disappearance were questioned by police and have not been charged with crimes.

A joint investigation Konanki’s disappearance is being conducted by the FBI, the US Embassy in the Dominican Republic, the Dominican National Police and the Dominican Prosecutor’s office, sources close to the investigation told ABC News.

The investigators will question everyone involved in the incident again, including hotel employees and the man Konanki’s friends say she was with before she disappeared, the sources said.

All security camera footage since the day Konanki and her five friends arrived on the island is now being analyzed, sources said.