Albert Calibet, 59, was last seen Tuesday while hiking on the Greek island of Amorgos. New drone video over the rocky terrain shows the extensive search efforts for the Hermosa Beach man.
A helicopter and local shepherds have also joined in to help find him.
Retired LA County deputy disappears while hiking in blistering heat wave in Greece
Surveillance video obtained by MEGA Live News, which is being investigated by Greek authorities, appears to show Calibet in a parking lot setting off on that hike.
"We're sick to our stomachs, knowing he's out there somewhere," said his girlfriend Debbie Leshane.
She said Calibet called her right before he was leaving for the hike. They spoke for six minutes, and then he sent her a photo at 9:20 a.m. from the trailhead sign. That's the last she heard from him.
Leshane and Calibet's brother traveled to the Mediterranean country with a couple of search and rescue people from Los Angeles.
Unfortunately, after a full day of searching Friday, the search was suspended. Efforts were expected to resume on Saturday at daybreak.
"The island is half the size of Catalina. It's not that big," said his brother, Oliver Calibet. "Time is of the essence... he's on the fourth day right now. It's not good, but we're very positive about it."
The scorching heat has posed a challenge in the search as parts of the country see triple-digit temperatures.
Temperatures exceeded 104 degrees Fahrenheit on Thursday in much of central and southern Greece, including greater Athens, the Cyclades and Crete.
Officials are on heightened alert for wildfires, which plague Greece every summer.
All of this comes as a second American and a tourist from the Netherlands disappeared separately on different islands. In addition, the body of a British TV personality was recently discovered after he also went walking in hot temperatures on another Greek island.
The Associated Press contributed to this report.