Maybe
It still seems odd to me though, as Grange was a case review, and surely that function ended.
Maybe the rationale is to keep the team together, as they are best placed to help the Germans
Yes the case review function was 2011- 2013, then the status changed and it became an investigation.
Operation Grange
"One Detective Sergeant and 3 Detective Constables are currently working on this investigation full time – the SIO as published is part-time, sharing his time between Op Grange and one of the Homicide teams in the MPS."
Status update of Operation Grange