Stone, 27, was playing for Al Ittihad Jeddah in the Saudi Arabia Elite Cup semifinals at the time.
"It really saddens all of us at U of L to see a young man like Marvin lose his life at such a young age," U of L coach Rick Pitino said. "Our deepest sympathies go out to the Stone family."
Stone played center for one season at U of L after transferring from Kentucky. As a senior in 2002-03, he started 23 games and averaged 10.3 points, 7.1 rebounds and 1.5 blocked shots.
Stone left UK after nine games into his junior season. He averaged 4.6 points and 3.8 rebounds as a freshman and 6.0 points and 4.6 rebounds as a sophomore.
Stone was a McDonald's and Parade All-American out of Grissom High School in Huntsville, Ala.