In the early-morning hours of April 11, Joshua M. Devine vanished during a boating trip to the scenic Similan Islands, a popular location for divers off the coast of Thailand. Five days later, that is still virtually all that is agreed upon about his disappearance.

Devine, 36, a U.S. Army veteran who deployed to Kosovo and Iraq, owns land in Thailand with his wife, Thadsana, family members said. He is an experienced diver, and was traveling with her on a dive boat traveling from Phuket, an island province in the Andaman Sea.

Devine disappeared around 5 a.m. while on a vessel contracted by the Mermaids Dive Center in the beach city of Pattaya, the company and family members said. The details are murky, however.

Witnesses told police that Devine was seen intoxicated before his disappearance, according to Thai media reports. Devine’s wife also told NBC News that he appeared drunk, and pulled lights from the wall about 4 a.m. believing that they were secret cameras.

“He was yelling and spilled beer everywhere and made a mess of the room,” Thadsana Devine told NBC News.

He went missing after other passengers attempted to calm him, Devine’s wife said. He was left alone for a short time, and was gone when others checked on him, she added.

Devine’s family has serious doubts about the story. As a trained diver with an even keel, it is highly unlikely that he would have been intoxicated just hours before a scheduled dive, said his sister, Jennifer Bakowski, of Enfield, Conn. He was typically “all business” when there were risks, she said.

“It’s utter nonsense, what they’re painting him as,” Bakowski told The Washington Post. “They’re painting him as some drunk American who landed in Thai water, and tough luck.”

Bakowski and her mother were planning to travel Thursday night to Thailand to get answers. Local media reports in New England, where Devine grew up, helped generate more than $10,000 online so they could make the trip.

The dive company said in a lengthy message posted on Facebook on Thursday that after learning Devine was missing, the dive trip “immediately searched the vessel,” and then doubled back to the area where he had last been seen.

“The dive boat then conducted an ocean search for the missing passenger in a logical, planned manner using large spotlights while many members of the dive trip assisted with torches,” the company said. “At the same time the boat captain started initiating radio contact with the Royal Thai Navy, Royal Thai Police, rescue services, as well as other vessels in the area. The location was not within cellular coverage.”

Mermaids Dive CenterPattaya, Thailand16 April 2015Mermaids Dive Center regrets to announce a passenger went missing…

Posted by Mermaids Dive Center 5 Star PADI CDC on Thursday, April 16, 2015

The company said that it continued to search until authorities arrived, but Devine’s family questions why the tour operator continued on with its dive trip afterward. Company officials said the boat departed the area where Devine was lost at 3 p.m., about 10 hours after he went missing, after police conducted their interviews. The company posted photographs on Facebook afterward of others posing happily for photos in the water.

“They allowed the boat to carry on for five days, so if there was any evidence of foul play, it’s gone now,” Bakowski said. “It’s pretty sloppy investigative work, if I say so myself.”

The company said in its Facebook message that it would not be answering additional questions, citing the open investigation. Devine’s wife, State Department officials, and Thai officials in Washington did not immediately respond to requests for comment.

Devine is a native of Holyoke, Mass., and enlisted in the Army after graduating from high school in the neighboring city of Chicopee in 1997, his sister said.

Devine left the military as a sergeant in January 2006, said Wayne Hall, an Army spokesman. He deployed to Kosovo from late 1999 to June 2000, and to Iraq from October 2004 to September 2005. He left the active Army after his original four-year contract expired, but re-enlisted in the Connecticut National Guard after the terrorist attacks on Sept. 11, 2001.