Sen. Johnson: We must 'get to the bottom' of Burisma-Biden connection
03:54Senator Ron Johnson (R-WI), the chairman of the Committee on Homeland Security, is with Ayman Mohyeldin explaining why his committee is pushing forward an investigation of Ukrainian energy company Burisma. Johnson says there are a lot of "unanswered questions" surrounding connections between Democrats and that company, and denies any political motivation behind the investigation.