A family of five was found dead inside their home in the municipality of Jalpa de Méndez in the state of Tabasco.
According to initial investigations, the father killed his three children, his wife and then committed suicide.
The crime occurred in the early hours of Monday in the town of Nicolás Bravo, where the bodies of three children aged 4, 6 and 7 were found with head wounds caused by a sledgehammer.
The 40-year-old mother was found with similar wounds on the face and body.
The father, who worked as a driver for a construction company, hanged himself.
According to the neighbors, the family was going through economic problems.