Agent Michael Ferlazzo said at a bail hearing that 37-year-old Irfan Khan appears to advocate violence repeatedly on some of the more than 1,000 phone calls the FBI recorded between him and his father, brother and other alleged conspirators.
On one call, Ferlazzo said, Irfan Khan referred to Pakistan's government as "big pimps."
"They're talking about violent opposition to the government," Ferlazzo said. On another call, the agent said, Irfan Khan seemed pleased that people feared the Pakistani Taliban "because of how lethal they had become."
Irfan Khan, his 24-year-old brother Izhar Khan and their father, 76-year-old Hafiz Khan, are charged along with three others in Pakistan - including Hafiz Khan's daughter, Amina - with four terrorism support-related crimes.
Prosecutors say they funneled at least USD 50,000 to the Pakistani Taliban, which is waging a violent campaign against Pakistan's government and has also targeted US interests. The Khans have pleaded not guilty. The three charged in Pakistan remain at large.
US District Judge Adalberto Jordan is considering bail requests from the two brothers, but he has rejected bail for Hafiz Khan. Jordan said he would decide on whether to release Irfan Khan on bail by the middle of next week. Attorneys for the brothers have argued there is little evidence linking them to terrorism.