That's something we've always liked to try to do, because in the average murder investigation.... I've heard differing comments on it, but if there is such a thing as an average murder investigation, it could be millions of dollars.
I can tell you one instance that I know of, a murder in Toronto that remained unsolved for nine years. Significant investigation time was put forward, there were hundreds of samples taken and screened, and the individual who was the perpetrator came forward through the retroactive provision. And they had solved that case 20 minutes after the sample came into the national DNA data bank.
I have no idea what that particular murder case would have cost over nine years, but you can understand there would have been substantial savings.