Half Moon Bay
If you have the Ripper Escapes card, as soon as all five of the victims have been played in front of any player, you immediately lay it down and the hand ends. This makes the game pretty tense towards the end of the deck, when it's likely that you or your opponent has the Ripper Escapes card, but you need to get rid of some victim cards.
I just checked the scanned rules, and it looks like the only requirement is having all five victim cards in play:
Ripper Escapes. This card is worth 35 points. It's not a Gavel card or an Evidence card. You may play this card at any time as long as all five Victim cards are in play. This means you could even play it during someone else's turn. You may play it in your play area as soon as the fifth Victim card comes into play, no matter what else you've done on that turn. As soon as the Ripper Escapes card is played, the hand ends.