The procession attracted more than 7,000 attendees, including California Gov. Jerry Brown.
At least a dozen helicopters circled the church, Grove Community Church in Riverside, during the procession.
Dozens of patrol cars and motorcycles trailed behind the hearse, escorted by two police cars, at around 8:30 a.m.
Crain, a former U.S. Marine, was buried at the Riverside National Cemetery.
Riverside Police Chief Sergio Diaz addressed the 34-year-old’s family at the service. Crain’s wife, Regina, as well as other friends of Crain’s spoke during the 90-minute funeral service.
The funeral also featured a slideshow with music including Jimi Hendrix and Eric Clapton, according to the Press-Enterprise.
Crain’s partner was also shot but is expected to recover, according to authorities. His identity has not yet been released.