 After the manifesto was published , the FBI received over a thousand calls a day for months in response to the offer of a $ 1 million reward for information leading to the identity of the Unabomber . There were also large numbers of letters mailed to the UNABOM Task Force that purported to be from the Unabomber , and thousands of suspect leads were sifted through . While the FBI was occupied with new leads , David Kaczynski first hired private investigator Susan Swanson in Chicago to investigate Ted 's activities discreetly . The Kaczynski brothers had become estranged in 1990 , and David had not seen Ted for ten years . David later hired Washington , D.C. attorney Tony Bisceglie to organize evidence acquired by Swanson and make contact with the FBI , given the likely difficulty in attracting the FBI 's attention . He wanted to protect his brother from the danger of an FBI raid , such as the Ruby Ridge or the Waco Siege , since he assumed Ted would not take kindly to being contacted by the FBI and would likely react irrationally or violently . 
