The search continues for a U.S. tourist that went missing on Tuesday after going on a solo hike on the Greek island of Amorgos.
The rescue team—made up of South Aegean Police Command officers, the Embassy, Coast Guard volunteers, the Amorgos Volunteer Rescue Team, and a group from the Greek island of Paros—have been coordinating the hunt across nearly a quarter of the island for 59-year-old Albert Calibet, according to a Greek newsite. An aerial search was also underway for Calibet.
A State Department spokesperson confirmed to TIME in an emailed statement that they were aware of reports of a missing person in Greece, and that they stood ready to provide assistance to U.S. citizens and families.
Calibet was “well-known on the island” due to numerous visits over the course of the past few years, Calliope Despotidi, the deputy mayor of Amorgos, told the Greek Reporter.
Authorities are currently attempting to track Calibet’s phone, and are also using drones to help facilitate the search. Calibet was last in communication with his sister on Tuesday when he sent her a photo of a trail sign, per the Greek Reporter. He was originally supposed to meet with a friend between noon and 1 p.m. local time, but never showed up.
Officials believe that Calibet deviated from his original hiking route, which was expected to take a travel time of just over four hours.
Calibet started working at the Los Angeles County Sheriff’s Deputy in 1998. Despite his retirement, he still worked at the department as a part-time employee. Calibet disappeared shortly after British TV doctor Michael Mosley was found dead on the Greek island of Symi. Authorities said Mosley died due to natural causes, though there are more reports to be done before ruling the official cause of death.
Greece has been confronting intense heat waves, with temperatures expected to reach up to more than 100 degrees Fahrenheit. Popular tourist sites like Acropolis Hill, along with multiple schools and nurseries, closed mid-week due to high temperatures.