CIUDAD JUaREZ, Mexico Forensic experts in Ciudad Juarez are trying to identify the remains of several bodies unearthed in the rural Valley of Juarez where a previous mass grave was discovered.
'They have gone out there again to locate more bodies,' said Oscar Hagelseib, Special Agent in Charge of Homeland Security Investigations in El Paso.
The U.S. agency provided intelligence that helped their Mexican counterparts locate the bodies in a region that has been the scene of some of the worst drug violence.
In November 2012, Mexican authorities uncovered the remains of 20 murder victims in the same area.
Homeland Security Investigations again worked with Mexican authorities to locate the new grave site and identify a victim from the U.S.
'We have reason to believe that a U.S. resident or U.S. citizen has been discovered in one of these grave sites,' Hagelseib said.
Mexico has a 'database of recovered remains' that can be used to match DNA from relatives of people who have been reported missing said Arturo Sandoval, spokesman for the Chihuahua Attorney General's office.
But there are conflicting reports about the number of decomposed bodies quietly pulled from the grave site this month.
'We recovered the remains of three men, and they have been dead four years,' Sandoval said.
He added that forensic workers would conduct further testing to verify the exact age of the remains.
According to several U.S. officials, seven bodies were recovered from the mass grave.
Authorities suspect there are more clandestine graves in the Valley of Juarez. The region became a battleground for cartels fighting for smuggling routes to the U.S.
Drug gangs terrorized the small Mexican towns located near the border, burning down homes, kidnapping and killing people.
Some of those targeted were involved in drug trafficking, but others were not.
'We know of individuals who have gone missing who have nothing to do with the drug trade,' Hagelseib said. 'Farms were just taken over by the cartels, and it could just be a worker who went to work one day.'
The violence forced some residents to flee, seeking asylum on the U.S. side of the border.
Adriana Olivas Cervantes who said her husband and 18-year-old son were killed last year because they 'found a grave site' in the Valley of Juarez while trying to fill a truck with dirt for a contractor.
'I was shot seven times,' Cervantes said. 'That's why I'm now seeking political asylum. It's an injustice what's happening,'
She said police failed to investigate.
Lorena Acosta said police officers killed her husband in October and dumped his body in Valley of Juarez last October.
Acosta, an elementary school teacher and U.S. citizen, moved to the area with her husband after he was deported in 2006.
'Upon entering, the officers started immediately firing their guns and shot my husband three times in the head,' she said.
Acosta said six officers burst into the home claiming, they were searching for an illegal gun.
After her husband's murder, his twin brother and uncle were then forced into a truck with his body, according to relatives.
'They were hit on the head with the butt of a gun, threatened, and they are alive to recount it,' said Guadalupe Estrella, wife of the surviving twin brother.
Estella said police drove the men to the area where the body was dumped, and warned the pair not to tell anyone about the murder.
'They threatened them, and told them to clean up the mess at our home... and that if anyone asked about my husband to say the Martians took him,' Acosta said.
She recovered her husband's body months later, after the family shared their story at a news conference with other asylum-seekers.
But others are still waiting for word about their missing loved ones. The latest remains discovered may hold some answers.
'It's very challenging for U.S. and Mexican law enforcement to identify these people and bring the culprits to justice,' Hagelseib said.