Authorities are intensifying search efforts by land and sea for the missing University of Pittsburgh student who disappeared one week ago while on spring break with friends in the Dominican Republic.

Sudiksha Konanki, 20, was last seen in the early morning hours of March 6 heading to a beach close to the Riu Republica hotel in Punta Cana with a group of friends. Polices say Konanki allegedly stayed behind with a man named Joshua Riibe who she met on the island. Surveillance video shows Riibe, a person of interest in the case, leaving the beach area hours later with Konanki. Riibe is not considered a suspect.

The Dominican Republic National Police is working closely with authorities from the U.S. Department of State, FBI, DEA, Homeland Security Investigations and the University of Pittsburgh police to investigate.

More: Disappearance in the Dominican Republic: Timeline of a mystery

The Dominican Republic Public Prosecutor’s Office on Wednesday said they were looking into whether Konanki’s disappearance extended “beyond a possible accidental event,” according to CNN. Konanki’s father, Subbarayudu Konanki, urged authorities earlier to pivot from the assumption that his daughter drowned and consider other options, including kidnapping.