the package felt like “three kilograms of brick narcotics that were bound together very tightly with tape.” See United States v. Rouco, 765 F.2d 983, 992 (11th Cir.1985) (explaining that prejudicial testimony is less likely to mandate a mistrial when there is other significant evidence of guilt that reduces the likelihood that the otherwise improper testimony had a substantial impact on the verdict of the jury). AFFIRMED. 1 . Miranda v. Arizona, 384 U.S. 436, 86 S.Ct. 1602, 1624, 16 L.Ed.2d 694 (1966). 2 . Because we conclude that no improper remark or substantial prejudice occurred, we reject Pineiro’s argument that the government’s line of questioning improperly shifted the burden to him to prove his lack of knowledge. See United States v. Simon, 964 F.2d 1082, 1086 (11th Cir.1992) (<HOLDING>). And even still, the district court properly
recognizing that a prosecutors comment may be so prejudicial as to shift the burden of proof and may require reversal if the misconduct is so pronounced and persistent that it permeates the entire atmosphere of the trial holding that the prosecutors comment regarding the defendants failure to call a potential witness did not shift the burden of proof because it did not implicate the defendants fifth amendment right not to testify holding that a prosecutor may comment on the absence of evidence so long as there is sufficient evidence to support the prosecutors version of events holding that prosecutors comment  if there was  evidence available to defense lawyers dont you think they would put it on  did not require reversal because district courts instruction  that burden was on the government  should have sufficiently erased any doubts as to which party had the burden of proof holding that erroneous admission of improper and prejudicial evidence did not require reversal because the jury would have returned a verdict of guilty against the defendant even without the prejudicial testimony