Capitol Police Officer Brian Sicknick suffered a pair of strokes and ended up dying of natural causes after helping to combat rioters outside Congress in January, but his death was not directly caused by the event, the DC medical examiner said Monday. The cop, 42, had been hailed a hero, with President Biden ordering an urn with his ashes to lie in honor in the Capitol Rotunda — the country’s top tribute to a late private citizen. Sicknick is only the sixth person in history to receive the honor, which also had been bestowed on civil-rights icon Rosa Parks, renowned televangelist the Rev. Billy Graham and three other Capitol Police officers killed since 1988. Congress’s top Dems, House Speaker Nancy Pelosi and Sen. Chuck Schumer, praised “the heroism of Officer Sicknick and the Capitol Police force during the violent insurrection against our Capitol’’ in a joint statement at the time. “His sacrifice reminds us every day of our obligation to our country and to the people we serve,” they said of Sicknick. The cop had collapsed after he returned to his office following the protests Jan. 6 and died about eight hours later.