Official reports said that the assailants arrived at St. Charles Borromeo Church and, after identifying one of the victims, began shooting. Authorities speculated that the shooting was to settle a grudge.
Ten people suspected of involvement in the killings have been arrested.
The Catholic Church in Colombia last year suffered the killing of seven priests, a nun and a seminarian.
The most serious attack involving the Church took place last May in Bojaya, where guerrilla bombs killed more than 100 people who had sought refuge in a church.
