Updated

Mexican security forces exhumed eight more bodies Wednesday from mass graves in a northwestern state capital where drug gangs are believed to have buried their victims, bringing the total from a monthlong search to 104.

The search at the pit at a car repair shop in Durango city appeared finally to be over, the Durango state attorney general's office said in a statement.

A total of 87 bodies have been found in that grave, including the eight discovered Wednesday. Seventeen other decomposed bodies were found in mid-April next to a well-known hacienda less than a mile from the car shop.

The graves in Durango are the second such discovery in a month: A total of 183 bodies have been unearthed in 40 pits in the northeastern border state of Tamaulipas.

Mass graves have become an increasingly common discovery in Mexico's brutal drug war, which has claimed more than 34,600 lives since President Felipe Calderon deployed thousands of federal security forces four years ago to fight traffickers. The offensive led to a splintering of the country's cartels and increased gang fighting over territory.

The pits found in Durango and Tamaulipas are the biggest discoveries yet.

Alejandro Poire, the federal government spokesman for security issues, said many victims in Tamaulipas are believed to have been killed after refusing to work as drug traffickers. A total of 74 suspects have been arrested in that case, including 17 municipal police officers from the town of San Fernando, where the 183 bodies were found.

Authorities first found the Tamaulipas graves April 1 as part of investigations into reports that gunmen had been kidnapping people from passenger buses in the state, which borders Texas.

State authorities across Mexico have sent reports of missing persons to Tamaulipas and families have lined up at morgues to give DNA samples. The process has been slow, with only two bodies identified so far.

Authorities in Durango state say the discovery of mass graves there has not brought out many relatives of missing people, perhaps because families are too frightened to come forward.