Idelfonso Zamora was warned last year that he would pay dearly if he continued his campaign against illegal logging in woodlands outside Mexico City. During a community march to call attention to the deforestation, two pickup trucks approached Zamora and, according to witnesses, the occupants yelled: “Your days are numbered. If you don’t back down we’ll give it to you where it hurts you the most.”

On May 15, Zamora’s 21-year-old son, Aldo, was shot to death and another teenage son seriously wounded when they were ambushed by four gunmen outside the family’s Tlahuica Indian community of San Juan Atzingo in Mexico State, about a two-hour drive southwest of Mexico City. The environmental group Greenpeace and Mexican human rights organizations say the attack provides the latest example of ongoing violence against rural activists in Mexico by illegal loggers and other special interests in league with corrupt local politicians and courts.