Seven Mexican soldiers being held in the June killings of 22 suspected criminals will be tried by a civilian judge, three of them for homicide, federal justice officials said Sunday.
The troops were ordered arrested Friday by a Mexico state judge for dereliction of duty in the June 30 incident.
Three of them are charged with aggravated homicide, and one of them with allowing a crime to take place.
For now, the soldiers are jailed in a military detention center.
In September, a witness said the gun battle itself had left only one dead, and the other 21 were killed in cold blood by the soldiers — including her 15-year-old daughter.
The case adds to the shock surrounding a more recent case of 43 students who went missing in the southern town of Iguala in late September. They were allegedly taken away and killed by police linked to a drug cartel.
If confirmed, the incident would mark one of the worst horrors in a drug war that has left more than 80,000 people dead since the conflict ramped up in 2006.