They aren’t investigating GPS. They are investigating Trump. That is what the letter appointing Mueller says.
Misleading. THe appointment letter give Mueller authority to investigate any matters arising directly from the investigation, and to prosecute and federal criminal acts according to his judgment.
Mueller has interpreted this so widely as to investigate Manafort and Gates for totally unrelated activity that occurred years before the 2016 campaign, yet he does not lift a finger to determine whether FusionGPS and associates were involved in a variety of dishonest acts, quite possibly criminal, to launch and steer the whole “Muh Russia” story.
https://www.justice.gov/opa/press-release/file/967231/download
“Mueller hasn’t asked to see the DNC server that was allegedly “hacked”. You’d think that would be central to the investigation...They aren’t investigating GPS”
Mueller should goon-raid the DNC HQ , Fusion HQ and their lawyers offices in the dead of night and seize all electronic data files. It is very possible that somewhere in those files there could be a Russian lurking about, or something, however indirectly, connected indirectly to a Russian. He can use one of those crooked judges he has on his payroll to issue the warrants.