Prosecutors in the northern Mexico border city of Ciudad Juarez say a gang of gunmen shot to death a man and three girls aged 4, 13 and 14, leaving behind 123 spent bullet casings.
Prosecutors in northern Chihuahua state said Monday that the gunmen also apparently kidnapped another man from the family's home.
The attackers fled following the killings Sunday on the outskirts of the city. The motive is still under investigation.
It was the latest in a series of children's deaths in Mexico. Many of the children have been killed in attacks on their parents.
Gunmen in Mexico were once relatively careful about not hitting children in targeted killings of adults. That is apparently no longer the case.