Michael looked at Samara in surprise and horror. He couldn't believe what he was seeing. Each dose of blood could last a year and a few months for a vampire of Diana's age. Having those vials in her possession meant that she had never given the blood to Diana.
Samara shook her head anxiously, "It's not what you think, Michael. Those vials shouldn't be in other hands, not even in hers. I can explain. If they found out where those vials were… she'd be in trouble."
Her little voice was layered with sadness and anxiety. Fear reflected in her eyes as she tried to explain. However, Michael knew that Samara was lying, but he didn't understand why. For years he believed in her and treated her like a sister.