The mother of two Australian surfers killed in Mexico made a touching tribute to honor her sons at a beach in San Diego on Tuesday.

"Our hearts are broken, and the world has become a darker place for us," Debra Robinson said as she fought back tears.

"They were young men enjoying their passion of surfing together."

Robinson's sons, Callum and Jake, were allegedly killed by car thieves in Baja California, just across the border from San Diego, sometime between April 28 and 29.

Robinson also commended the American, Jack Carter Rhoad, who was killed alongside her boys.

The San Diego beachside, where the tribute took place, was chosen purposefully as it's right across the border from the Baja California city of Tijuana.

She mentioned that her son Callum "considered the United States his second home," while her son Jake loved surfing so much that, as a doctor, he preferred to work in hospitals close to the beach, according to the Associated Press.

Choking back tears, the grieving mother delivered a final message that matched her sons' adventurous lifestyles.

"Jake's passion was surfing, and it was no coincidence that many of the hospitals that he worked in were close to surfing beaches," she said.

They were reported missing on April 29 after failing to check in to their Airbnb.

Their burned-out white pickup truck was dumped 40 miles away from where their bodies were subsequently found.

The three men had been shot to death.