Enrique Plancarte died in the central state of Queretaro, officials told the AP.
He was considered one of four leaders of the Knights Templar cartel, which is based in Michoacan state.
The gang has been chased out of many Michoacan towns by vigilante gunmen (like the one shown above) that have demanded authorities go after the gang's leaders.
In recent weeks, Mexican security forces killed the gang's top capo, Nazario Moreno.
-- Bill Miller