Philip Vannatter was a senior LAPD robbery-homicide detective who was described as "a beefy, slow moving cop with a head of caramel colored hair." Vannatter was one of the first detectives at the murder scene, arriving at 4:05a.m. There he worked with other detectives, including Fuhrman, in investigating the crime scene. As the LAPD employed over 1400 detectives, Vannatter had never met Fuhrman prior to the Simpson case.

It was Vannatter's decision to contact Simpson. He believed that Simpson may need some assistance in retrieving his two children from the police station, where they had been kept in police custody since being discovered sleeping on the night of the murders. Vannatter decided that the four detectives he was working with at the crime scene should make the trip to Simpson's home. While at Simpson's Rockingham mansion, the detectives noticed the blood on Simpson's Bronco. Rationalizing their initial warrantless entrance onto Simpson's Rockingham Mansion property, Vannatter testified that he had just left a brutal crime scene and that he "felt that someone inside that house may be the victim of a crime, maybe bleeding or worse."

The defense sought to implicate Vannatter in "framing" Simpson for the murder of Brown-Simpson and Goldman by suggesting that Vannatter was part of the wide-ranging LAPD conspiracy to frame Simpson for the double murder. When asked whether in his 25 years of service with the LAPD he had ever been falsely accused of conspiring to frame someone for murder, Vannatter replied, "[y]ou bet I have."