Officials with the US Marshal's service in Bexar County confirmed Monday that Gunselman was arrested last Thursday.
No other information about his arrest--including a mug shot or whether he will be transferred to Lubbock--was available.
Gunselman is accused of selling fake carbon credits to international oil and gas companies in an elaborate scheme that netted him $50 million.
Many of Gunselman's properties and most of the money in his bank accounts were seized when the federal investigation began last October but he was allowed to stay at a house in Lubbock.
Gunselman had previously purchased a home in Bexar County that had been owned by a professional basketball player.
A warrant for his arrest was issued last week by the US Secret Service, who is the lead agency investigating the crime.