A grave was dug up by police after a "credible" tip-off that guns had been buried in the plot.
West Midlands Police said no weapons had been found during the excavation, which was carried out at Birmingham's Brandwood End Cemetery.
In a statement confirming the grave was examined while the cemetery was closed on the evening of May 27, the force said no human remains had been disturbed.
The statement added: "West Midlands Police obtained a licence from the Ministry of Justice earlier this year to excavate a grave plot in Birmingham.
"The excavation happened in private, behind a screen while the cemetery was closed, and the team carried out the search with the utmost sensitivity and respect.
"The process followed credible intelligence received by police about firearms being buried at the location."
The intelligence was corroborated before the excavation by a non-intrusive scientific scan of the plot, which showed the presence of an unexplained metallic mass roughly two feet below the surface.
A police spokesman said: "We don't take the decision to open a grave lightly and all alternative courses of possible action were considered.
"We suspected potential weapons were just a couple of feet below the surface of the ground and it's our duty to ensure they don't end up in the wrong hands."
The spokesman was unable to confirm or deny a media report that champagne bottles were found in the grave, believed to be that of a stabbing victim who was buried several years ago.
The family of the deceased were informed of the excavation before it took place and relatives were offered the opportunity to be present.