The grave, around 10 kilometres (6 miles) from the port of Veracruz in the east of the country, was located in the same area as another grave holding hundreds of victims, which was found in 2016, also as a result of a tip-off.

Rosalia Castro Toss, spokesperson for the Solecito collective – made up of mostly mothers of missing persons -told reporters the map was handed to the group a few months ago. Now, they are awaiting permits to carry out a search.

Close to the grave’s apparent location is a road to relieve traffic heading to the port. The surrounding terrain is covered with vegetation, and has repeatedly been the scene of criminal activity.

Veracruz state, which stretches along the Gulf of Mexico coast, has suffered heavily at the hands of organised crime and has one of the country’s highest rates of missing persons.

Since 2006, when the government deployed the army to fight drug trafficking, more than 200,000 people have been murdered. Official figures say more than 30,000 are missing.