The massacre occurred early Christmas Day outside a house in the village of Puente del Rey, where the gunmen shot dead the six men and one women, aged 24 to 54.
Those killed were three brothers, their father, their uncle, and a man and a woman who were invited to the home.
Guerrero is one of Mexico's states most affected by brutal drug gangs which frequently battle each other, as well as carrying out kidnappings and extortion.
It recently earned international infamy as a region where 43 students in 2014 went missing, and were presumably murdered, at the hands of corrupt police working for criminals.
