Retired Los Angeles Sheriff's Deputy and Dutch Tourist Missing in Greece

Two tourists – one a retired Los Angeles sheriff's deputy and the other a Dutchman – disappeared while on a separate hiking trip in Greece, local authorities confirmed.

Albert Calibet, a 59-year-old Californian, disappeared Tuesday afternoon, shortly after embarking on a four-hour hike on the Greek island of Amorgos. He was last seen on his way to the village of Katapola, according to a statement posted on the official Facebook page of the municipality of Amorgos.

Since then, several agencies have joined the search for Calibet, including coast guard volunteers and crews from the neighboring islands of Paros and Naxos, according to Greek public broadcaster ERT News. They are also using a drone to search the northernmost part of the island.

Calibet – a former cop and veteran hiker – has been going to Amorgos “almost every year” for about a decade, Popi Despotidi, Amorgos' deputy mayor for tourism, told CNN on Thursday.

His brother Alex Calibet said he was particularly worried given the hot weather currently ravaging most of Greece. According to the Hellenic National Meteorological Service, the heatwave is expected to peak on Thursday and so the agency has issued an orange alert, its second most severe designation.

“We're almost three days here,” Alex Calibet said on Fox 11. “There's no water…I'm very distraught.”

Searches were also underway on the island of Samos to find a 74-year-old Dutch tourist who had been missing since Sunday. He disappeared while hiking in the Marathokampou region, the Hellenic Samos Rescue Team said in a Facebook post. The efforts include “police, firefighters and volunteers,” Konstantia Dimoglidou, a Greek police spokeswoman, told CNN.

“Unfortunately, we have not heard from any of them so far,” she added.

The separate searches follow the discovery of the body of British television personality Michael Mosley, who went missing while walking in hot weather on the Greek island of Symi earlier this month.

Mosley, a television doctor who popularized a type of intermittent fasting called the 5:2 diet, was found dead Sunday and an autopsy showed he died of natural causes. Authorities believe he died on June 6, just hours after he began his walk.