"Sad news: the number of dead has risen to eight," Munich police said on Twitter.
A police spokesman later told reporters that the dead body of a man had been found near the shopping centre and investigators were trying to determine whether he was one of the assailants.
"The possibility that this was someone involved in the crime is currently being closely examined," he said.
A male witness speaking to rolling news channel NTV said he saw one of the gunmen at the mall "dressed as Father Christmas and wearing sunglasses".