Timeline of when gunman was spotted to when shots rang out during Trump assassination attempt

Secret Service members at former President Donald Trump's rally last Saturday were notified by Pennsylvania State Police officers about a suspicious person with a rangefinder at 5:51 p.m., about 20 minutes before the gunman shot at Trump, according to three sources familiar with a law enforcement briefing to members of Congress on Wednesday. CBS News correspondent Charlie De Mar has the latest on the investigation.