It was the Chief of the US Capitol Police, which is different from DC (city) police. I doubt that the US Capitol Police has the expertise & competence to fully investigate the computer and potential espionage aspects. This should have been an FBI case from the start (not that the FBI is always so reliable, either, but at least they have far more relevant staff and experience).
The heat on this needs to be turned way way up. This whole thing should be treated as a potential espionage case, for onee thing. Foreign nationals from a nation which is a hotbed of terrorism, getting extensive access to House files, including everything handled by sensitive committees such as the House Intelligence Committee.
We need some prominent national figures to demand that all intel sharing with House Democrats cease until this case has been completely investigated and until much much better security/computer standards are in place.