(CNN) -- To a friend of more than 20 years, Manssor Arbabsiar was a man who liked to be called "Jack" and didn't seem to have strong views on politics or religion. 

To U.S. authorities, the 56-year-old naturalized U.S. citizen is a suspect in an alleged Iranian plot to assassinate Saudi Arabia's ambassador to the United States. 

"It was shocking because it didn't seem like he would be the type of person to do something like that," said Mitchel Hamauei, who said he met Arbabsiar through mutual Iranian friends. 

"He was a happy go lucky guy, always joked around," Hamauei said. "He had a really happy demeanor." 

Hamauei, who runs a gyro and kebab restaurant in Corpus Christi, Texas, said the two were close enough that he attended the graduation of Arbabsiar's son. 

"I know his wife and his son. They're very down-to-earth people," Hamauei said. 

The two kept in touch even after Arbabsiar moved to Austin about four or five years ago. 

"I saw him about a year ago. He came by the store to eat a sandwich." 

Arbabsiar was a used car salesman, Hamauei said. Their conversations would be about "life in general," he said. "Nothing religious. Nothing political." 

"He would go out and party," Hamauei said. "As far as I know he never practiced religion." 

Martha Guerrero, Arbabsiar's estranged wife, told the Austin, Texas, station KVUE Tuesday that they've "been separated for a long time" and she doesn't know anything about his affairs. 

However, she believes he is innocent. 
Would he keep to himself at home?
He would go out and party,"