Arrest at Houston Airport

"Officers said they then found the brass knuckles, as well as several books and diagrams in his carry-on luggage, including one book titled, "New Voices of Islam," and another espionage publication called "Spycraft."

Officers said many of the books were written in Arabic, but they did notice English publications that refer to "jihad" and "infidels." They also found diagrams that purport to describe U.S. military weaponry, according to law enforcement officials who spoke on the condition of anonymity."

In addition to the publications, thumb drive, and the brass knuckles confiscated by police, investigators said that Kumar had a large amount of cash that had not been declared to Customs officials as part of his travel."

Investigators said that Kumar claimed he was in Houston for some sort of "Islamic seminar."