MEXICO CITY (AP) — The mother of two Australian surfers killed in Mexico delivered a moving tribute to her sons Tuesday at a beach in San Diego.

“Our hearts are broken and the world has become a darker place for us,” Debra Robinson said, fighting back tears. “They were young men enjoying their passion of surfing together.”

Her sons, Callum and Jake, were allegedly killed by car thieves in Baja California, across the border from San Diego, somewhere around April 28 or 29.

Robinson also mourned the American who was killed with them, Jack Carter Rhoad.

The beachside location where she spoke, across the border from the Baja California city of Tijuana, was no coincidence. She noted that her son Callum “considered the United States his second home.”

Robinson noted that her son Jake loved surfing so much that, as a doctor, he liked to work in hospitals near the beach.