Documentary follows the investigation of a mysterious death during the Vietnam War

Jimmy McDowell served in Vietnam during the war. After his honorable discharge, he returned to the country as a civilian, where he died under mysterious circumstances in 1972.

Filmmaker Peter McDowell was just 5 years old when his older brother died. He spent 10 years investigating what happened.

“I just had a lot of questions that went unanswered,” McDowell said.

Growing up, McDowell said his brother’s death was shrouded in silence and mystery. It haunted his family. In 2012, he decided to find out everything he could about his brother. The documentary “Jimmy in Saigon,” premiering Wednesday at the GI Film Festival in San Diego, documents his search.

In the film, McDowell travels across the United States in search of answers. His questions take him to France and Vietnam.

McDowell, who is gay, said his family often wondered whether a romantic interest brought his brother back to Vietnam more than 50 years ago. There are also questions about his brother’s sexuality, he said.

“I wasn’t too sure about his sexuality because of something my mother said,” McDowell said. “It was probably a lot harder in the late ’60s and early ’70s.”

The film has been playing at festivals for a year, but McDowell said this is its first screening at a military and veterans-themed festival.

“We’ve been to mainstream festivals (and) LGBT festivals,” he said. “But we’ve never been to a military or veterans film festival, so I was looking forward to it.”

“Jimmy in Saigon” opens at the Museum of Photographic Arts at the San Diego Museum of Art on Wednesday at 7:45 p.m.