Mukhtasar Muslim (Abridged) 476 — Regarding five takbirs

Sayyiduna Abdur Rahman bin Abi Laila says that Zaid (may Allah be pleased with him) used to say four takbirs in our funeral prayers, and once he said five takbirs over a funeral. So I asked him, and he said that the Messenger of Allah (peace and blessings be upon him) (would also sometimes say five takbirs).