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."
More top news
Jeremy Corbyn underlined Labour's zero-tolerance approach to racism as he launched a report into anti-Semitism within the party.
A look at tips and advice to help keep children safe on the internet and reduce the chances of them being groomed online.
Boris Johnson has said he will not be standing in the race to succeed David Cameron as the leader of the Conservative party.