Initial relief turned to grief for Trilogy International Partners as it learned that five members of its wireless subsidiary in Haiti were killed in the earthquake or its aftermath.

The largest U.S. company in Haiti, Bellevue-based Trilogy provides mobile phone service through its Voilà subsidiary, which has about 575 employees.

Company executives initially thought the local workforce in Haiti had escaped without casualties. An inspection by its head of security following the earthquake found that all five of its buildings in Port-au-Prince remained intact, and the earthquake happened before the office closed for the day. Many employees returned to work Wednesday.

Yet a few days later Trilogy learned that five employees had died and about 35 others remain missing, said Carol Wilson, Trilogy's international compliance director.

Dozens of employees lost immediate family members and about 95 are without homes. The company's offices were filled with people camping out on the floor, Wilson said. The company is posting regular updates on the situation in Haiti here.

Trilogy engineers managed to get its network back up last Wednesday and it remains the only operational cellphone service in Port-au-Prince, but "the issue is congestion," Wilson said. Huge volumes of traffic are straining the network.

The company set up the non-profit Voilà Foundation to direct donations to relief efforts. Trilogy Chairman John Stanton and his wife, Theresa Gillespie, have pledged at least $1 million, and Trilogy International Partners has pledged $3 million.

A group of structural engineers flew from Seattle to Haiti today to go through the buildings to check further for structural damage.