“kill” will only kill one screen window. To “kill” the complete session, use quit.
Example
$ screen -X -S [session # you want to kill] quit
For dead sessions use:
$ screen -wipe
You can kill a detached session which is not responding within the screen session by doing the following.
Type screen -list to identify the detached screen session.
~$ screen -list
There are screens on:
20751.Melvin_Peter_V42 (Detached)
Note: 20751.Melvin_Peter_V42 is your session id.
Get attached to the detached screen session
screen -r 20751.Melvin_Peter_V42
Once connected to the session press Ctrl + A then type :quit