approach here. >> reporter: given the stakes of this hearing for next week, there have been mock hearings that republicans on the republican judiciary committee have had with a top aide playing robert mueller. also the house intelligence committee democrats had an aide standing in in their version of a mock hearing. that typically does not happen. we're also learning about the specific areas that they want to probe. first with the house judiciary committee democrats, they're going to focus on obstruction of justice. five areas in particular they want to hone in on. that includes the president allegedly telling the former white house counsel don mcgahn to fire the special counsel, telling mcgahn to publicly deny reports that trump told him to fire robert mueller. also telling corey lewandowski apparently, the former campaign manager, to tell the then attorney general jeff sessions to essentially limit the scope of the investigation to exclude the president and instead focus on future campaigns, and then telling lewandowski if sessions didn't meet with lewandowski that trump would fire sessions.