Story highlights Authorities have found a clandestine mass grave near Mexico City

A lawyer believes the bodies could be linked to a bar disappearance

12 youths were disappeared from a Mexico City bar in May

Officials say it could take days to identify the bodies

A clandestine mass grave found near Mexico City may hold the answer to what befell 12 youths who were kidnapped from a bar in the capital back in May.

Federal investigators swarmed a ranch east of Mexico City on Thursday, where they confirmed that at least seven bodies had been found, and that two arrests were made near the location.

A lawyer representing the families of five of the missing, however, told CNNMexico that he received a call from a source who said the bodies of the youths may be found there. The lawyer did not reveal his source.

The apparent kidnapping of the 12 youths from an after-hours club called Heavens shocked residents of Mexico City, who for the most part have been spared from the violence seen in other areas.

The lawyer, Ricardo Martinez, said his source told him there were 13 bodies found at the ranch, possibly in two mass graves, one that held the remains of the males, and the other, the females.

Mexico City's attorney general on Thursday said there was one grave so far that was being investigated.

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Officials have not confirmed the identities of the bodies, and CNN could not independently confirm the claims of the attorney.

Martinez said that a suspect in the disappearance of the youths led authorities to the ranch.

Mexico City Attorney General Rodolfo Rios said investigators were taking DNA samples to identify the remains, which could take several days.

The site where the bodies are found is the town of Tlalmanalco, in the state of Mexico, about 30 miles east of Mexico City, the state-run Notimex news agency reported.

Local, state and federal police were all at the scene.

A gang was involved in the mass disappearance, officials have said.

The May 26 incident at the after-hours bar jolted the capital city, given it took place in daylight on a Sunday morning.

Video footage shows a gang of about 17 people arriving in eight vehicles at the fashionable Zona Rosa district, according to authorities.

The owner of the bar, a co-owner and two bar employees have been arrested in the case.