The retired LAPD detective was 70 years old and died of complications from cancer at a Santa Clarita hospital.
Vannatter was among the first detectives on the scene at O.J. Simpson's mansion in June 1994, following the double murder. He testified at the murder trial, at which Simpson was acquitted.
He also led the 1977 investigation that led to the arrest of film director Roman Polanski on charges he had unlawful sex with a 13-year-old girl.
A 28-year veteran with the LAPD, where he spent most of his career as a homicide detective, Vannatter retired from the force in 1995, but continued on as a consultant for cold case murders. His brother Joe said Vannatter worked some 250 murder cases in his career.
Services are planned for Wednesday at Forest Lawn Memorial Park in Hollywood. A fund has been established in Vannatter's name with the Los Angeles Police Memorial Foundation.
Vannatter is survived by his wife, his daughter and a son, who is also an LAPD officer.
The Associated Press contributed to this story.