Galveston police identified the body as 26-year-old Calvin Mbwambo, an exchange student from Tanzania.
On the day the body was found, Mother's Day 2020, detectives had very little to help figure out who he was because no identification was present.
The only clues were the swim trunks, Calvin Klein briefs he had on, and size 11 Under Armour slides tied to his hands.
The crime scene photos were shared only with ABC13's Courtney Fischer, and the case was featured in ABC13's Unsolved series.
Later that year, the Galveston Medical Examiner's Office and the Galveston Police Department partnered with Othram, a private lab based in The Woodlands, to see whether DNA testing and forensic genetic genealogy would lead to the identity of the young man.
Dr. Kristen Mittelman, chief development officer at Othram, said the case sometimes felt hopeless. Soon their technology would help detectives solve what sometimes felt impossible.
"When we uploaded to the genealogical database, we realized that he was from East Africa and not an African American male in the United States," Mittelman said. "Then we did further analysis because there were no good matches in the database that would allow us to piece back his family tree and allow us to identify who he was."
Mittelman said it narrowed the scope tremendously once they could build a comprehensive profile and pinpoint he was originally from East Africa.
"It allowed us to tell law enforcement this is probably someone not from the United States, that is of this specific age, and maybe had come to the U.S. on a visa, and that's when the investigation started to go that direction," Mittelman said.
According to Mittelman, they then searched through documents and public records of foreign exchange students who had come to the Houston area and gone missing.
A fingerprint match showed yes, in fact, the body was Calvin, Mittleman said. "Science is advancing so quickly, and there is so much more you can do with this DNA profiling, and there is always a way to get results," she said.
Galveston police confirm the 24-year-old's family in Tanzania has been notified, giving the family answers and closure after years of searching.
"I think knowing the truth allows people to seek justice for what happened and spend the rest of their lives looking for someone," Mittelman said.
One of the lead detectives with Galveston police could not tell ABC13 yet where the exchange student was studying. While detectives said foul play is not suspected, they did say his identification allows them to re-open the case and look into what led to his drowning.
"How can you get justice if you don't have someone's name? Now law enforcement knows Calvin's name, and they will investigate the last people he was with, where he was, what school, what had happened the last few weeks of his life," Mittelman said.
DNA testing cannot tell us why Mbwambo was in Galveston or what happened leading up to his death. Those are questions detectives will work to answer.
Mittelman hopes this will give families in similar situations much-needed hope.
"I would hope the families don't lose hope," Mittleman said.
"I would hope they advocate for this technology on their case if they can, call law enforcement and alert them, advocate for funding for this technology that will help more cases get solved, and enter your DNA into DNAsolves.com because that database is only to help law enforcement identify perpetrators and victims," she said.
You can learn more about Othram on their website, access their media library of videos and images, and check out any of their cases here.