Just like in previous incidents they:

1. asked the ship raise its anchor, and move to a safe anchorage in Finnish territorial waters.

2. It was boarded inside Finnish territorial waters and seized there.

The police was in contact with ship's flag state, Saint Vincent & the Grenadines. Flag state can give permission to board the ship if it's not complying.

Seizing a ship in international waters is a serious violation of sovereignty unless it falls under very specific exceptions outlined in UNCLOS: piracy, slave trade, illegal broadcasting, or drug trafficking. Also ships without nationality have no protection and can be boarded by anyone.

Just drop those 14 overboard and let them swim back to Russia.