Possible Clues:

• Murderous
• Murderous criminal: 'I'm a child with nothing to hide'
• Brutal house — end up with police probing origin of law-breaking
• Murderous loch maid I upset
• Briefly in one detective group, say Capone is likely to kill
• Wanting to kill someone else?
• Like Shelley's deaf and viperous character, capable of administering a draught of woe