MEXICO CITY, Mexico (CNN) -- Three men have been arrested for a grenade attack last week on a crowd of revelers in Morelia that left eight people dead and 106 wounded, officials said Friday.
The suspects were arrested Thursday in the city of Apatzingan in the western state of Michoacan and are members of the Zetas, one of two groups fighting for control of the drug trade in the state, the republic's sub-attorney general in charge of organized crime told reporters Friday.
The Zetas are an armed wing of the Gulf cartel, Maricela Morales Ibanez added. The other group is La Familia.
The incident started at about 11:05 p.m. on September 15 when a fragmentation grenade exploded in Morelia, the capital of the state, as the commemorative bell was rung in celebration of Independence Day in the Plaza Melchor Ocampo.
Shortly afterward, another fragmentation grenade exploded on a city street corner.
A tip submitted Wednesday to police anonymously led to the arrests, the official said in a written statement.
He identified the suspects as Julio Cesar Modragon Mendoza, Juan Carlos Castro Galeana and Alfredo Rosas Elicea, who were taken to Mexico City.
CNN's Mario Gonzalez contributed to this story from Mexico City.