Unauthorised access

Hi.  Today my son answered a call from "internet tech support", who told him to install TeamViewer on our PC (which he did).  I was unable to find out from him what else went on (he's completely clammed up, knowing that he's done the wrong thing).  I've unplugged my PC from the network, however it was "live" for a good five hours.  I need to know what went on during that time - did this scammer access my PC?  If so, what did he do whilst connected?

This may necessitate police involvement, depending on what information was accessed.

I've not yet uninstalled TeamViewer, so any logs should still be intact.  Whom should I contact for help here?  Best case scenario, my son didn't manage to fully enable the client-side connection.  Worst case scenario, my family's personal and financial records are now for sale on some dark-web website.  I'd like to know at which end of the scale we're at.

Thanks in advance.