San Diego County Sheriff's Department: Cold Case Solved - Santee

Imperial Beach CA

18 March, 2022

8:50 AM

Description

Press release from San Diego County Sheriff's Department: March 16, 2022 On May 2, 1988, Diane Lynn Dahn did not arrive at work for her shift at the San Diego Transit Corporation. A coworker went to Diane's apartment in the 8700 block of Graves Avenue in Santee and discovered her body inside her bedroom at around 1:30 p.m. Her son was found wandering in the apartment complex. The San Diego County Sheriff's Homicide Unit responded and assumed responsibility for the investigation. An extensive investigation was performed to identity a suspect. The County Medical Examiner's Office conducted an autopsy on Diane. She had been bludgeoned and stabbed. The cause of Diane's death was stab wounds to the chest and the manner of her death was homicide. In October 2000, DNA was identified from samples taken from Diane's fingernails. Unfortunately, the profile did not yield a suspect. Further testing was done in 2001, but the profile was insufficient to place into a federal database of DNA from unsolved crimes or Combined DNA Index System (CODIS). In June 2010, the Sheriff's Homicide Unit's Cold Case Team reviewed Diane's case for additional leads and use of new technology. A hair, which had been found in Diane's hand, was processed. A profile was developed and submitted to CODIS with no results. The profile was consistent with the sample found under her fingernails. In May 2020, the Cold Case Team, in coordination with the Sheriff's Crime Lab, started working on Diane's murder using investigative genetic genealogy. After a year and a half of DNA testing and collection of familial samples, detectives developed investigative leads and identified a suspect: Warren Robertson. An intensive investigation into Warren Robertson's life reveals he was born in Arkansas, but spent most of his younger life in the San Diego region. In 1988, Robertson lived in the same apartment complex on Graves Avenue as Diane did. Robertson worked as a local tow truck driver. Soon after the murder, Robertson left his family and moved to Lakeside before moving to Indiana in late 1989. Robertson lived in Indiana until his death in a house fire on November 25, 1999. Robertson was 39 years old at the time of his death. Through further DNA testing, Robertson was determined to be the donor of the previously unknown DNA. The investigation revealed substantial and convincing evidence that Robertson had murdered Diane. Cold Case detectives did not determine Robertson and Diane knew each other. However, both were known to be race enthusiasts and attended stock car races at the El Cajon Speedway during the time of her murder. This press release was produced by San Diego County Sheriff's Department. The views expressed here are the author's own.