A man identified by two law enforcement sources as Ricky Shiffer, who died in a confrontation with police after he fired a nail gun at a Cincinnati FBI building, appeared to post online in recent days about his desire to kill FBI agents shortly after former President Donald Trump’s Mar-a-Lago residence was searched. Two law enforcement officials confirmed Shiffer’s name. Shiffer was at the Capitol riot on Jan. 6, 2021, according to three people aiding law enforcement who saw him in photos taken from the day of the attack; however, it’s unclear whether he went inside the building. Shiffer frequently...