"If no party has anything to hide then a full investigation should be welcomed by all"
EXACTLY!
All of Biden's family and friends should be thoroughly investigated. All of their bank records, personal holdings, emails, phone records, everything. A complete audit is needed. This should extend to his time as VP and members of the last Administration.
And of course, any illegal activity that is found not to be related to the investigation should be passed off to other agents for additional scrutiny.