Senior Liberal Democrats have not entered the row which has seen David Cameron back Chancellor George Osborne's comments that the case prompted "wider questions about our welfare system."
Mr Alexander said: "The Philpott case is an individual tragedy. Children have died in that case.
"I think that is where we should let that case lie. I would not want to connect that to the much wider need to reform our welfare system."
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Turning wet and windy from the west overnight.
The former shadow business secretary Clive Lewis made the comments at an event backed by Momentum.
Look up to the sky this weekend, and you might catch sight of one of the greatest natural spectacles of the year: The Orionid meteor shower.