The family of missing University of Pittsburgh student Sudiksha Konanki has asked police in the Dominican Republic to declare her dead, a police spokesman said Monday.

Dominican Republic National Police spokesperson Diego Pesqueira said Konanki’s family has sent the agency a letter requesting a declaration of death.

Konanki, 20, was on spring break with friends in the Caribbean island nation when she disappeared early March 6. Despite an extensive search, her body has not been found.

The Konanki family did not immediately respond to a request for comment Monday night.

Konanki is a junior in biology at the University of Pittsburgh. She is from Loudoun County, Virginia, where her family lives.

Konanki was last seen early March 6 after she went to the beach with friends.

After her friends left the beach, she stayed behind with people she met on the trip. She vanished after 4:15 a.m. that day.

The last person thought to have seen Konanki has been identified as Joshua Riibe, 22, a senior at St. Cloud State University in Minnesota who is from Rock Rapids, Iowa.

Dominican authorities confiscated Riibe’s passport Friday as part of an investigation, his attorneys told NBC News.

NBC News spotted Riibe with investigators and his attorney on a beach in Punta Cana early Sunday. He was seen pointing toward the sea while a group of security officials kept people away from the area.

Speaking exclusively to NBC News briefly at the resort where Konanki had been staying before she disappeared, and before he was spotted by NBC News on the beach, Riibe said, “I’m just trying to help them out,” adding: “The ocean is a dangerous place.”

Riibe “has been confined to the hotel since the investigation began. He is permanently escorted by the police anywhere he goes. So no, he is not free to leave,” the law firm representing him said in an email Saturday.

Pesqueira, the national police spokesperson, said no signs of violence were found at the beach.

A hotel spokesperson said red flags — which indicate “that the sea had a strong current and very high waves” — were flying when Konanki disappeared.

In an interview last week with Dominican investigators, Riibe said he was on the beach with Konanki shortly before she disappeared.

He said they were “in waist-deep water, talking and kissing a little,” according to a transcript of the interview obtained by NBC News. A wave crashed, taking them both “out to sea,” it quotes him saying.

“I kept trying to get her to breathe, but that didn’t allow me to breathe all the time, and I swallowed a lot of water,” he said.

Riibe said he got Konanki back to shore before she disappeared.

“The last time I saw her, I asked if she was OK. I didn’t hear her answer,” he said. “I looked around and didn’t see anyone. I thought she’d grabbed her things and left.”

Authorities in the Dominican Republic have said no one is considered a suspect in Konanki’s disappearance.

U.S. authorities have said it is a missing persons case and not a criminal matter.