Salcedo was the assistance principal at El Monte High School and a school district trustee. Many in the crowd were young people who say they've been influenced by Salcedo.
"He was an amazing person and because of him I am where I am today. And I'll continue to use his inspiration to continue my education," said former student Andy Fernandez.
Late last month, Salcedo was in Gomez Palacio in the state of Durango with his wife and friends when gunmen burst into a restaurant and kidnapped Salcedo and five other men and shot them.
Investigators have no motive for the attack and no arrests have been made. Mexican authorities believe the attackers were working for a cartel.
The Associated Press contributed to this report.