Preliminary medical examiner findings said Graham died after an aortic dissection tied to hardened arteries, undercutting social media claims that the South Carolina Republican was killed.
Posts on X blamed Russia, Iran, Ukraine and Israel, while others cited his recent Ukraine travel and FBI assistance to local authorities as supposed evidence of foul play.
Graham had announced a Russia sanctions package with the Trump administration on Friday and was a prominent hawk on Iran, Russia and Israel, making his sudden death a magnet for geopolitical conspiracy theories.
Communication experts said the abrupt death of a polarizing national figure often accelerates misinformation because dramatic explanations can feel more satisfying than a medical cause.