killing tunnels for a user connected with ssh -N

I created a forward only ssh connection with the following:

ssh -i id_rsa -o TCPKeepAlive=yes -o ServerAliveInterval=10  \ 
    -N -n -R 127.0.0.12:8888:127.0.0.12:8888 fwduser@192.168.1.201

Mow, on the server, I would like to disconnect that connection. If the user is connected with a shell session then pkill works but if it is a forward only connection, then I can't disconnect.

I tried pkill -u fwd user and it only works if the user has a connection. I tried to look in the list of processes and it does not appear

Does anyone know how to disconnect a forward only connection?