The afternoon of amateur football, largely attended by families, was drawing to a close when armed men stormed the grounds near the city of Salamanca in Guanajuato state on Sunday.

Guanajuato’s Security Secretariat issued a statement Wednesday saying the three arrests “resulted from various coordinated and targeted operations.”

The agency declined to share the identities of the arrested suspects as well as the charges against them due to the confidential nature of the investigations.

Five of the victims were security guards at the football pitch, all of whom were unarmed.

A preliminary investigation indicated the guards were targeted because they had worked for a company linked to the powerful Jalisco New Generation Cartel (CJNG).

The suspected attackers are believed to be part of the Santa Rosa de Lima cartel, which is based in Guanajuato and involved in a dispute with CJNG.