A spokesman for Nick Clegg said an Algeria-related tweet sent from Lib Dem MEP Graham Watson's account was "sick and offensive."
We have not been able to verify whether this tweet is authentic.
But whoever it is from, it is clearly sick and offensive and utterly condemned by Nick Clegg.
The tweet, since deleted, read: "Al Qaeda 1, @David_Cameron 0".
I'm told Mr Clegg was "furious" when he heard about the message. The party is still stressing, however, that they can't be sure Mr Watson himself sent it.
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Marjorie and Michael Cawdery, both 83, are understood to have been stabbed to death in a killing their family called "incomprehensible".
Detectives have launched a murder investigation following the shooting in Brent, north west London on Friday night.
Hot and humid throughout the Bank Holiday Weekend.