Friend of overdose victim: Google exec's prostitute was behind boyfriend's death

There are new twists in the case of a high-end prostitute who is now linked to two deaths.

Investigators are digging into the background of Alix Tichelman, the high-end prostitute who allegedly left a Google executive to die on his yacht.

Modeling, monkeys and Marilyn Manson: The world of Alix Catherine Tichelman

Police say she left a digital trail that suggests she is a callous and calculated killer - leaving a California father of five to die on his yacht after injecting him with a lethal dose of heroin.

Just months earlier, Dean Riopelle also died turned up dead from a heroin overdose.

CNN's Erin Burnett speaks to Riopelle's friend, Alan Vine.