On May 6th, Sierk's computer was hacked by someone in Omni Commons who accessed his computer when he left it unattended. They took over his Facebook account, replacing it with a "Dillinger - Public Enemy No1" logo and sent direct messages to me, and to another person at Omni who was hacked in the same way a few weeks earlier.
They also took over Sierk's Google account including his telephone number, and created a Signal account with his number, and communicated to me from all those accounts claiming to be Sierk.
I finally talked with Sierk in person (on May 7th) and confirmed that none of the accounts were in his control, and he had no way of getting back control of his Google account. Last night he asked me (in person) to tell people at the Omni that they should disregard messages appearing to come from him (including over SMS/text messaging), which are now asking for money.
Sierk says that people should ONLY trust in-person communications with him for the time being. He can often be found at Omni, working on his computer upstairs.
-Jake