Merida, Venezuela ? Investigators searched through the shattered wreckage of a plane that slammed into an Andean mountainside with 46 aboard, working in freezing temperatures Saturday to find clues and recover victims’ remains.

Sixteen specialists, including crash investigators and forensic experts, were dropped off by helicopter near the crash site on the steep, foggy slope at an altitude of 13,500 feet, said Gen. Ramon Vinas, head of the civil aviation authority.

Amid the wreckage, searchers recovered the plane’s two “black boxes” – cockpit voice and data recorders that could indicate what went wrong. Investigators say the pilot made no distress call before the crash.

Officials said the victims, mostly Venezuelans, also included five Colombians and a U.S. citizen, Vivian Guarch, 53, who worked for a Miami branch of Stanford Bank.

Weeping relatives of the victims prayed in a Mass in nearby Merida, arranging white roses in the shape of a heart on the floor of the church.

The twin-engine plane shattered on impact and burst into flames Thursday, leaving only its tail largely intact and a swath of blackened ground amid scrub brush. Searchers spotted the crash site by helicopter on Friday in the Sierra La Culata National Park.

“We’ve run into many difficulties due to the steepness of the terrain,” Vinas said. High winds forced the helicopter to leave the team more than a mile from the site, requiring them to hike in thin air and subfreezing temperatures to reach it.

Firefighters carried oxygen canisters to help cope with the high altitude.

Venezuelan officials said the recovery and identification of bodies would be difficult because victims were ripped apart upon impact.

“We’re going to recover everything we can,” emergency management chief Gen. Antonio Rivero told The Associated Press.