The Santa Cruz Sentinel reported Tuesday that surveillance video from the boat shows 51-year-old Forrest Timothy Hayes, a Google executive, losing consciousness.
Investigators say the suspect, Alix Catherine Tichelman, makes no effort to help him and instead gathers her belongings and even gulps a glass of wine before leaving. Hayes's body was discovered the next day.
The 26-year-old from Georgia was taken into custody last week after being lured back to Santa Cruz County in a prostitution sting.
She faces charges including second-degree murder.
Police say Tichelman provided heroin for Hayes while they were aboard the 50-ft. yacht.