Marco Antonio Higuera, the state attorney general for Sinaloa, where the van was found, made the announcement today (Dec. 15) in a statement.
Julio Cesar Muniz, Martin Rogelio Muniz and Sergio Simon Benitez have been arrested, so far. Two other suspects have been identified but are still at large, the statement said.
Lucas and Coleman were on a surfing trip but failed to show up as expected in Guadalajara City on Nov. 21, according to an appeal for their whereabouts on Facebook.
Their van was found near the coast about 120 miles south of where they were last seen and about 300 miles north of Guadalajara. The region is known for its lawlessness and powerful drug cartels.
The bandits were dressed in police uniforms and apparently had staked out a stretch of Benito Juarez Highway intent on robbing someone.
Coleman was believed to have been shot when he tried to resist the robbers. Both men were forced back into their van and driven to a dirt road in a desert area north of Navolato, a small town. Coleman and Lucas were shot at the scene, said the spokesman.
Once the news hit home, friends shared moving tributes to the surfers. A fundraising page on gofundme was launched to help their families defray funeral expenses, according to Facebook.