Google executive Forrest Hayes being fatally injected with heroin by prostitute Alix Tichelman revealed on CCTV

Dramatic footage showing Google executive Forrest Hayes being injected with a fatal dose of heroin by a high-cost prostitute, shortly before his death by drugs overdose, has been obtained by prosecutors.

CCTV footage shot on Hayes' private yacht reportedly shows prostitute Alix Tichelman injecting him with the class A drug.

Hayes had just accepted a job at Google X: a secretive lab for developing new projects by the web search giant.

Father-of-five, Hayes is shown cavorting with Tichelman on board the boat, somewhere off the coast of Santa Cruz in California. He then allows her to inject him with heroin.

It was previously supposed no video footage existed of Hayes' death and prosecutors fought a three-month legal battle to secure the tape, which will be crucial evidence in Tichelman's upcoming trial.

The 28-year-old "dancer" is charged with manslaughter, as well as charges relating to drugs and prostitution.

Police chief Steven Clark recounted what is revealed in the video: "She brought the drugs. We see her prepare the syringe. It looks like she's injecting herself, but her back's to the camera.

"He watches this happen. And then she eventually injects him. I get the impression he's nervous. He's uncertain. But he's going along with it," he said.

Soon afterward, Hayes suffers a reaction to the heroin which would turn out to be fatal. Tichelman allegedly failed to seek help by calling emergency services.

Clark said: "She is literally walking around the cabin of the boat, stepping over him, grabbing her glass of wine, carrying it around the boat cabin."

"That's seven minutes emergency medical personnel could have reacted to this situation to save Mr Hayes' life. That's the crux of the case."