The killers prowled through Loma Bonita in the pre-dawn chill.
In silence, they navigated a labyrinth of wood shacks at the crest of a dirt lane in the blighted Tijuana neighborhood, police say. They were looking for Margarito Saldaña, an easygoing 43-year-old district police commander. They found a house full of sleeping people.
Neighbors quivered at the crack of AK-47 assault rifles blasting inside Saldaña's tiny home. Rafael García, an unemployed laborer who lives nearby, recalled thinking it was "a fireworks show," then sliding under his bed in fear.
In murdering not only Saldaña, but also his wife, Sandra, and their 12-year-old daughter, Valeria, the Loma Bonita killers violated a rarely broken rule of Mexico's drug cartel underworld: Family should remain free from harm. The slayings capped five harrowing hours during which the assassins methodically hunted down and murdered two other police officers and mistakenly killed a 3-year-old boy and his mother.
The brutality of what unfolded here in the overnight hours of Jan. 14 and early Jan. 15 is a grim hallmark of a crisis that has cast a pall over the United States' southern neighbor. Events in three border cities over the past three months illustrate the military and financial power of Mexico's cartels and the extent of their reach into a society shaken by fear.