36-year-old Marine Corps veteran Drew DeVoursney moved to Belize in December last year.
There, he met and fell in love with 52-year-old Francesca Matus, a Toronto native who was also living in the Central American country.
Drew was due to move back to America in May, and Francesca – a mother to twin 22-year-old boys – was due to fly home to Canada. Just one day before her flight, the couple went missing.
The pair were last seen around 11pm on April 25, leaving a bar in Belize's Corozal District. When a friend - who was due to drive Francesca to the airport for her flight home - arrived at her house the next morning to find them both missing.
Less than a week later, the bodies of Francesca and Drew were found in a remote village.
Drew's mother, Char DeVoursney, told PEOPLE Magazine the couple's hands had been duct-taped and it appeared the pair had been strangled.
Francesca's vehicle was found around 10 miles away.
Char says the U.S. Embassy told her her son and his partner had been "murdered", and that their bodies "were in an advanced state of decomposition."
Both Canadian and U.S. authorities are working to determine what happened to the couple.
A GoFundMe page set up by Drew's best friend is now raising money to help fund a private investigation into the deaths.
Char is now mourning the loss of her "adventure boy", who served served two tours in Afghanistan after enlisting as a marine after the September 11 terrorist attacks.
He had moved to Belize to teach people how to dive.
"He just kept pursuing the next thing he wanted to do and he was really good at it," she said.
Francesca's friends and family have also paid tribute to her on social media, remembering her as having a "zest for life".
"Her smile was infectious and could light up a room...she will be deeply missed," wrote on friend on Facebook, while a family member added, "you are so very loved".
"I promise we will find out who did this to you."