law enforcement sources tell CBS News that Phoenix has become ground zero for the explosion in the reported number of kidnappings and home invasions involving drug traffickers and criminals with connections to the Mexican drug cartels.

A CBS News investigation has discovered that as of last weekend, there have been 266 reported kidnappings and 300 home invasions this year alone. Sources say the real figures could run as much as three times higher because so many go unreported.

In June, three Mexican nationals were arrested by Phoenix police after a violent home invasion and murder at a drug "safe house." They were dressed head-to-toe just like the local S.W.A.T. team - and just as heavily armed.

Now CBS News has learned enforcer gangs just south of the Mexican border have added military-grade hand grenades to their arsenal - something special agent Jose Wall expects to see in Phoenix any day.

From what’s known of it, the package — officially dubbed the “Mérida Initiative” but more commonly referred to as “Plan Mexico” -- contains direct donations of military and intelligence equipment, and training programs for Mexican law enforcement officials. A White House fact sheet lists surveillance equipment, helicopters and aircraft, scanners for border revisions, communications systems, and training programs for “strengthening the institutions of justice.” An additional $50 million dollars is earmarked for Central American countries to support their fight against “gangs, drugs, and arms.”