Acting on an anonymous tip-off, Mexican authorities discovered another mass grave on Monday, this time in the northern border state of Sonora, media reports said Tuesday.
Eight bodies, including six men, one woman and a girl, were found in two clandestine pits along a dirt road near the city of Navojoa, in the south of the state, which is a key drug smuggling route to the United States.
The gruesome discovery was made after police received a phone call from a member of the public about the burial site.
Given the state of the remains, medical experts estimate the victims may have died as long as 18 months ago.
Last week investigators further south pulled more than two dozen bodies from two mass graves, one on the Michoacan-Jalisco state border and another in Acapulco.
More from GlobalPost: Another day, another mass grave uncovered in Mexico
On Sunday, a family of eight was stabbed to death in the border city of Ciudad Juarez, in Chihuahua state. A three-month-old baby survived the brutal attack.
News of mass graves and massacres has been a constant in Mexico in recent years. More than 70,000 people have been killed and another 26,000 have been disappeared since the previous administration unleashed federal security forces against powerful drug cartels in December 2006.