Hundreds of mourners attended a funeral on Thursday for two American Mormons murdered in a northern Mexican community by drug hitmen for denouncing cartel kidnappings, and the FBI offered to aid a police probe.

Guarded by Mexican soldiers, more than a thousand people, including family members, wept over the coffin of Benjamin LeBaron, a breakaway Mormon leader and anti-crime activist who was abducted and killed by around 20 armed men in revenge for helping track and arrest a group of drug gang members.

Gunmen broke into LeBaron's house on Tuesday night and tortured him in front of his family before dragging him off along with his brother-in-law, Luis Carlos Widmar, shooting them dead and dumping their bodies in nearby countryside.

The outcry over the killing was the latest blow to President Felipe Calderon and his army-led quest to curb rampant drug gang violence that has killed more than 12,300 people across Mexico since he took office in December 2006.

The men who murdered them have no children, no parents, no mother, community leader Adrian LeBaron told a packed church in Chihuahua state near Texas, where blonde-haired Mormons of Germanic origin settled in the 1920s from the United States to practice their staid lifestyles and polygamy.

The group broke away from the mainstream Mormon church when it abandoned plural marriages.

Mexican police say drug gangs ordered the killings. The U.S. Federal Bureau of Investigation has offered to help in the investigation, the U.S. Embassy in Mexico City said.

For years, ruthless drug gangs have silenced crime reporters and activists by murdering or threatening them.

In recent months, some have turned to abducting dozens of Mormons in the farming and ranching community of LeBaron.

Hitmen kidnapped LeBaron's brother Eric in May, provoking the community's 2,000 residents to hold protests in the state capital of Chihuahua. They refused to pay a $1 million ransom.

Even after Eric's release, residents -- many of whom are dual U.S. citizens -- held protests to plead for police protection in the remote desert lands of Chihuahua state. Chihuahua officials attended the funeral on Thursday and promised improved security.

Calderon's government has urged citizens to be vigilant and report drug gang crimes to aid his crackdown. But many Mexicans are too fearful to alert authorities because corrupt police often openly work with the drug gangs.

Bloodshed from drug gang turf wars has alarmed Washington, which fears the killings are spilling over its border, and has become a major concern for investors.

Mexico Religion