In a series of social media posts, Jack Schlossberg, a frequent critic of the Trump administration, said his family was not given a “heads up” about the release.

Jack Schlossberg, the only grandson of President John F. Kennedy, was not among the many people poring over the new trove of government files about Kennedy’s assassination when it was released Tuesday. Instead, Schlossberg was on social media criticizing President Donald Trump, Republican lawmakers and the news media over the handling of the files.