Is suicide prohibited in Bible?

There're two descriptions of suicide in Bible. One is by Saul and the other is by Judas of Iscariote. Two examples represent most cases. Political or natioanl leader who lost the war ends up in this act and those who lost all hopes and left only despair also do the same thing.Recently we were amazed to hear one Catholic believer killed two people and committed suicide. I think some Christian church have taught those who killed himself cannot get a key for afterlife, though, I don't think there's direct reference in Bible that prohibits this act.Have any suggestions ?