article_snippet: Her family have had to wait 13 agonising years for answers .
article_snippet: Despite the offer of a $150,000 reward and the release of composite sketches of two male suspects in 2012, an arrest was never made.
article_snippet: But detectives persisted with the case, using new DNA technology, surveillance footage, witnesses and clues from gang members who had relinquished their criminal past.
article_snippet: For the first time, officers now believe officers have a timeline for LA County police lieutenant Dave Coleman's final hours.
article_snippet: Questioning: These composite sketches of two male suspects were released almost three years ago.
article_snippet: Lt Coleman claimed the force has 'worked tirelessly to bring Lt Coleman killers to justice'.
article_snippet: the force are still looking for outstanding witnesses.
article_snippet: Lt Coleman said: 'We hope that anyone with knowledge of this horrific incident will overcome any fear of coercion or retaliation and come forward and bring justice to Brenda's   and Brenda's   family.'