( CNN ) -- At least five of the bodies found this week in a shallow grave near Mexico City are those of teens who were kidnapped from a bar three months ago , Mexico 's attorney general said Friday . The announcement appears to shed light on a crime that jolted the capital city : The kidnapping of 12 youths from an after-hours club during daylight on the morning of May 26 . Authorities on Thursday said they found a clandestine mass grave east of Mexico City . On Friday , the federal attorney general said the grave -- a shallow grave covered by concrete at an eco park in a state neighboring Mexico City -- contained 13 bodies . Five of them were those of youths who 'd been taken from the Mexico City club , the attorney general said . Earlier , authorities said the grave was at a ranch . The site is in the town of Tlalmanalco , in the state of Mexico , about 30 miles east of Mexico City , the state-run Notimex news agency reported . Authorities have n't said what led them to the grave . The May 26 incident at the after-hours bar shocked residents of Mexico City , who for the most part have been spared from the violence seen in other areas . The owner of the bar , a co-owner and two bar employees have been arrested in the case . Mexico : As dangerous , and safe , as ever . CNNMexico 's Veronica Diaz and Juan Pablo Mayorga contributed to this report .
13 bodies found in mass grave near Mexico City this week . Of those 13 , five have been identified as youths kidnapped from Mexico City bar . 12 youths were kidnapped from after-hours club in May , authorities say . Four people have been arrested in the case .