basic sign

When i'm outside i mostly move with my bicycle.
Today when i was riding along the near park a cyclist passed me and made a sniffing noise, then i past a jogging woman who also made this noise, and past the next street crossing there was another cyclist who did so.
This wasn't loud, but they all did exactly the same noise to insure that i know that it's no incident. They were all three within maybe 300meters.
The sniffing noise is in use since 2000, it was added to a gesture : pointing with the finger at the nostril, wich is in use since 1999.

Yesterday(Monday) i had an anonymeus phone call, someone tried to phone me at least half a dozen times, because no number appeared on the display(only "privat") i thought he could speak on the box, he didn't, at the end i took the phone, no one answered, just listened a while, then hung up.