CHICAGO, March 23 (UPI) -- The parents of a Marine who survived Iraq and was gunned down in Chicago joined the man who received their son's heart at a news conference Saturday.

Ricardo Martinez and Adalila Cruz first met Brian Troy of Rockford, Ill., about a month ago -- almost two years after their son, Lance Cpl. Ricky Martinez, was killed. Troy, who served in the Marines in the 1980s, had been trying to get in touch with them after guessing, from reading news reports, that he had Martinez's heart, the Chicago Tribune reported.

"The first year we didn't try to find out, with all the pain and grieving," Cruz said. "But it got to the point where I thought, 'What's done is done, I want to meet the person who has my son's heart.'"

They decided to hold a news conference to publicize the need for organ donations and to lobby for stiffer penalties for attacking veterans.

Cpl. Martinez, who did two tours in Iraq, was shot and killed as he and some friends drove home from a Cubs game. Police say the shooter believed a member of a rival gang was in the car.