pm-suspend does not call the lock screen on resume

Dear all,

I just noticed that running `$ sudo pm-suspend` does not lock the screen on resume from suspend. I know that I can use the suspend option from the wingpanel menu at the top. However, I am using the following small function to create a suspend timer:

standbyTimerPM () {
 bash -c 'echo "System is going to standby in $1 minute(s)..."
    sleep $1m
    sudo pm-suspend' -- $1
}

Does anyone know how I can force the lock screen to be executed after running pm-suspend to have a lock screen presented on resume?

Thanks!

Robert