Like Mr. Cruz, who was ordained a pastor in 2004, the Casters are devoted Christians. The name Mannatech stems from the biblical manna, food provided by God to the Israelites in the desert, and Mrs. Caster wrote a book, “Undeniable Destiny,” in which she described herself, Mr. Caster and the company as instruments of divine will.

Through his wife, Mr. Caster declined to speak about Mr. Cruz. But Mrs. Caster said she recalled Mr. Cruz being a successful sales associate who translated Mannatech literature into Spanish and served as an interpreter during business trips to Mexico. She crossed paths with Mr. Cruz on occasion in the 1990s in the Mannatech office in a Dallas suburb and on two “incentive cruises” where top-selling associates were rewarded.

“He was very friendly, very outgoing, really a nice person, easy to talk to,” Mrs. Caster said. “Being a Christian, there are people who are up there who don’t have integrity, who don’t represent well. I felt he was not like that, that he was a sincere person and engaging.”

Mr. Cruz was never personally sued or charged with violating any laws. The allegations about attempts to sell products in Mexico appeared in a lawsuit filed by shareholders, in which Mannatech was accused of inflating its value through improper sales tactics.

According to the lawsuit, first filed in 2005 in United States District Court in New Mexico, the company had allowed a sales associate to place large orders for Mannatech products and then distribute them to customers in Australia and New Zealand without approval from those countries. That allowed the company “plausible deniability” because it would appear that the associate was acting alone, the lawsuit said.

Mannatech “intended to do the same thing to gain a foothold in Mexico,” according to the lawsuit.

This claim was attributed to an unnamed former project manager who served as a confidential witness in the case and went on to describe an encounter with Mr. Cruz. The project manager had relatives in Mexico and was asked by Mr. Cruz whether those relatives “were interested in taking in Mannatech products and redistributing them to potential customers in Mexico,” according to the lawsuit.