With his receding hairline and blue-rimmed spectacles, Orson William Black Jr looks innocuous, harmless even.
In fact, US authorities believe Black is a very dangerous man, certainly a paedophile and possibly even a triple killer.
Black and 26 of his followers, including four wives and a "concubine", were arrested when up to 100 agents from the FBI, the Chihuahua prosecutor's office and the US Department of State descended on his heavily fortified compound last Friday, reports news.com.au
The bureau claims the 56-year-old is the fugitive leader of a polygamous cult - a breakaway sect of the controversial Fundamentalist Church of Jesus Christ of Latter-Day Saints - which has been operating in the desert highlands of northern Mexico for more than a decade.
Black has been a wanted man since 2003, when he fled sex crimes charges filed in Arizona, which accused him of sexual misconduct against minors - believed to include two 13-year-old brides.
Arizona news reports at the time indicated that Black viewed himself as a "prophet" or "archangel".
The raids came three weeks after the bodies of three Americans - a boy and two men - were found at cult's sprawling property Rancho El Negro, or Black Ranch.
Mexican authorities identified the slain victims as Michael B, 15, Robert WB, 19, and Jesse LB, 23. They are thought to have been gunned down execution-style at the entrance of Black Jr's trailer.
The trio share the surname Black - as do all of the cult leaders followers, according to local media - but Mexican authorities have confirmed that two of the victims, Michael B and Robert WB, were the polygamist's sons.
None of the residents holed up at the compound had passports or identification papers and authorities were still trying to ascertain the parentage of Jesse LB.
"The motive has not been clarified and is still being investigated," Chihuahua prosecutor's office spokesman Felix Gonzalez told the Los Angeles Times.
The victims were found on one of five properties owned by Black, Gonzales said.
The ranch where the slain men were found, like the settlement where Black was arrested, is situated in the sprawling Chihuahua municipality of Cuauhtemoc, the heart of the country's large Mennonite population.
"The two groups would appear to be unlikely neighbours," the Times reported.
"Mennonites, who began settling in Mexico in the 1920s after emigrating from Canada, practise a conservative, pacifist Christian faith that views marriage as a lifelong monogamous commitment between a man and a woman."
Authorities said a total of 27 Americans "with an illegal status in Mexico" were in custody, including "four wives and one concubine".
Prosecutor's spokesman Carlos Huerta told AFP there were minors within the group but did not specify how many or what their ages were.
Black has been charged with offences ranging from immigration breaches to human trafficking and is a suspect in the three murders.
In a bizarre twist, authorities also found the stuffed heads and body parts of more than 50 exotic animals including a peacock, an owl, zebras, buffalo, black squirrels, a lion, chickens from Peru, red foxes and goats.
As a result, the cult members have also been charged with crimes against biodiversity.
The raids went down after Mexican authorities became suspicious that none of the young people killed or loved ones who came to claim their bodies had birth certificates.
Orson William Black Jr "was wanted for 15 years for crimes of a sexual nature in the United States and fled to Mexico", the prosecution said.
The website of the US Department of State places him as "fugitive" in a brief file.
Investigators are trying to determine how Black had access to funds to buy land and other assets during his time in Mexico.
Mexican authorities also seized a dozen vehicles at Black's compound, with both Mexican and US licence plates. Chihuahua shares a long border with Texas and New Mexico.