A person of interest in custody in the Dominican Republic in the disappearance of a University of Pittsburgh student earlier this month has been forced to surrender his passport while he undergoes questioning by authorities.

According to a statement from his family, Joshua Riibe is a 22-year-old senior at St. Cloud State University in Minnesota and was on vacation but not traveling with the group that included missing Pitt student Sudiksha Konanki, WTAE reports.

“It is our understanding that he is a US citizen who was vacationing in Punta Cana, not part of the group traveling with the missing person,” officials with the sheriff’s office in Loudon County, Virginia, where Konanki lives, said.

Konanki, 20, vanished from the beach at the Riu República Hotel in Punta Cana early on March 6, as CrimeOnline reported. Riibe is believed to have been the last person with Konanki on the beach.

Officials say that Konanki and five other Pitt students, all women, traveled to the Dominican Republic for spring break, WTAE reported. Sources told the station that the group went to nightclub then went to the beach at about 4 a.m. on March 6. The other women in the group were seen on video returning to their hotel rooms just before 6, without Konanki, who reportedly stayed behind with a man, believed to be Riibe.

Riibe reportedly told officials he went for a swim with Konanki and they were caught by a big wave. The sources say Riibe returned to the beach and passed out, then later returned to his hotel room, unsure what happened to Konanki. He said he had assumed she would be all right since they were only in knee-deep water.

In their statement, Riibe’s family said that Riibe “is deeply dismayed by [Konanki’s] disappearance and has fully cooperated in the search and clarification of the facts from the beginning.” They added they the circumstances of his detention have been “irregular” and that he has been “subjected to extensive questioning wihout the presence of official translators or legal counsel” until the middle of last week.

“We ask everyone to pray that Sudiksha be found and returned home to her family,” they added.

The chief prosecutor is expected to make a statement about the case on Monday.