EL PASO, Texas (Border Report) – Mexican authorities have identified 19 of the 20 people shot to death Sunday in a clandestine cockfighting ring in Zinapecuaro, Michoacan.

The victims include three U.S. citizens whom the Michoacan Attorney General’s Office only identified by first names: Melissa S., Salvador A. and Jose Abiel A. The latter allegedly was the owner of the unlicensed cockfighting arena inside a ranch called El Paraiso (Paradise); the woman was one of three females killed in the attack.

KION-TV identified the deceased woman as Melissa Silva, 36 and a mother of four, and said her sister, Arleth, 16 and a resident of Chicago, was among six wounded. The station quoted their brother, Alex, as saying the sisters were vacationing in Mexico, where family members live.

The AG’s office said it received assistance from the U.S. Embassy in Mexico to verify the identities. It’s also working with the Embassy of Guatemala to verify the identity of the alleged target of the attack, a man so far only known as “El Chapo de Guatemala.”

“We have been able to establish, through investigations, that alleged members of a criminal cell that operates in Eastern Michoacan were (at the arena),” state authorities said in a news release.

No arrests were reported as of Wednesday in the attack in which gunmen wearing camouflage arrived to the ranch in a food truck and blocked the exit to the facility with a hijacked public transportation bus.

After the shooting, state police found more than 100 shell casings of 7.62-caliber bullets typically used by AK-47 rifles, .223-caliber shells used by AR-15 rifles and .40-caliber pistol casings. The AG’s Office said some of the vehicles parked near the scene bore stickers and held clothing with the logos of a drug cartel.

Mexican news reports identified that group as the Jalisco New Generation Cartel, which has been at war with the Familia Michoacana criminal organization and a local gang called Los Correa.