Grant appointed David Dyer, under Bristow's recommendation, federal attorney to prosecute the Ring in St. Louis, who indicted Grant's old friend General John McDonald, supervisor of Internal Revenue. Grant endorsed Bristow's investigation writing on a letter "Let no guilty man escape..." Bristow's investigation discovered Babcock received kickback payments, and that Babcock had secretly forewarned McDonald, the ring's mastermind boss, of the coming investigation. On November 22, the jury convicted McDonald. On December 9, Babcock was indicted, however, Grant refused to believe in Babcock's guilt, was ready to testify in Babcock's favor, but Fish warned that doing so would put Grant in the embarrassing position of testifying against a case prosecuted by his own administration. Instead, Grant remained in Washington and on February 12, 1876, gave a deposition in Babcock's defense, expressing that his confidence in his secretary was "unshaken". Grant's testimony silenced all but his strongest critics.