MEXICO CITY , Mexico ( CNN ) -- Six members of one of Mexico 's most active drug gangs , including someone accused of being the organization 's bookkeeper , were arrested this week , federal authorities said Wednesday . Federal policemen stand at a checkpoint in the state of Michoacan last week . The arrests were the most recent in a string of high-level apprehensions targeting La Familia Michoacana ; the cartel operates in its namesake state of Michoacan in southwest Mexico . Armando Quintero Guerra , who federal police said was in charge of the cartel 's expenses , was among six people arrested Tuesday , said Ramon Eduardo Pequeno , head of the anti-drug unit of the public security ministry . Also arrested was Lourdes Medina Hernandez , who is in a relationship with La Familia 's top boss , Servando Gomez , Pequeno said at a news conference . The string of arrests followed the killing of 12 off-duty federal police officers whose bodies were found with signs of torture off a remote highway on July 14 . Hit men for La Familia Michoacana linked to the killings were arrested last week , authorities said . Authorities more than tripled the number of federal police officers patrolling Michoacan in response to the killings . The killings were among a series of reprisals by La Familia after federal police captured one of the group 's top leaders , authorities said . An unprecedented wave of violence has washed over Mexico since President Felipe Calderon declared war on the drug cartels shortly after coming into office in 2006 . More than 10,000 people have died in that time span , about 1,000 of them police . CNN en Español 's Rey Rodriguez contributed to this report .
Arrests part of a string of high-level apprehensions targeting Mexican drug cartel . La Familia Michoacana suspected in slayings of 12 federal police officers this month . Man accused of being group 's bookkeeper arrested Tuesday , authorities say .