Complex sentence: On 6 April 2011, the Mexican authorities exhumed 59 corpses from eight mass graves; by 7 June 2011, and after a series of multiple excavations, 193 bodies were exhumed from the mass graves in San Fernando.
Split into simpler sentences: On 6 April 2011, the Mexican authorities exhumed 59 corpses from eight mass graves. By 7 June 2011, after a series of multiple excavations, a total of 193 bodies were exhumed from mass graves in San Fernando.