 Earlier in the evening, Baker had substituted Alex Hellman's insulin (Hellman being diabetic) with a lethal dose.Hellman, the last to die, has previously savagely murdered Bert with a hammer, this after Bert has strangled Christina in the shower after her return from Baker's home.With Bert, Christina and Baker all dead - Alex returns home in a state (having never murdered anyone before) and takes his lethal substituted medication.