On November 18 I contacted investigator Marina Medvedeva and asked how the preliminary inquiry was going. From what she said, I understood that her part of the work was done and she was no longer even handling my case.
So on November 28 I sent an online inquiry to the Investigative Committee, addressed to D. V. Gerasimenya.
On December 22 D. V. Gerasimenya replied that I should communicate with him about my case.