Well, one would assume that the police work of the time was done to the most reasonable extent possible and if the outcome of that police work was him as a susp

Well, one would assume that the police work of the time was done to the most reasonable extent possible and if the outcome of that police work was him as a suspect, being able to confirm DNA at the murder scene would only serve to affirm that suspicion. It all depends on what other evidence police based their suspicion at the time. The person who bought the shawl said he consulted the original written police reports in the archives. I suppose anyone could do the same, or... buy the book. ;)