Police: We have got the last girl to go missing with your DNA and the one before with your
DNA, both on their naked bodies. How can that be?
Steve Wright:  No comment.
Extract from Suffolk police interview from 20 December 2006
Guardian Online, 21 February 2008
After the disappearance of a second prostitute working in Ipswich’s red light area in the winter of 2006, Suffolk Police link the killings and launch a double murder investigation codenamed Operation Sumac.

Despite a team which includes officers from nearly every police force in the country, a record number of calls from the public and nearly 10,000 interviews, detectives are unable to find anyone who’d seen the bodies being dumped or the weapons used to kill the victims.
Steve Wright is careful to try to dispose of all evidence linking him to his five victims, cleaning his car and his clothes. However, detectives would find enough traces remaining for forensic examiners to establish a link. Ray Palmer, a lead forensic scientist is one of the hundred experts used in the Suffolk investigation. Palmer and his team find Wright's DNA on three of the women's bodies, while microscopic fibres from his clothing, car and home were discovered on all five.
Another challenge facing investigators was to establish a link between Wright and the missing woman. The answer is to view footage from the many CCTV cameras used in Ipswich and its red light area. Inspector Steve Griss from the specialist CCTV Unit uses surveillance systems and an automatic car number plate reader to identify Wright’s Ford Mondeo car. Suffolk officers wade through up to 10,000 hours of footage to find answers to their questions. Eventually they discover footage showing Wright was in the red light area at the key times when each of the five women had disappeared.
After the one of the largest and most intense police investigations ever undertaken, Wright was finally caught by tireless police work and extraordinary forensic evidence.