Detective Gary Williams was investigating a rape last year when his leads dried up. From the victim's statement, he knew there had been a witness to the crime, he even knew his name, but the person had not come forward and could not be found at their registered address.

So Williams, of South Yorkshire Police in the UK, turned to a smart search engine the force had begun trialling only 2 hours earlier. With just the name of the witness, the Intelligent Data Operating Layer (IDOL) trawled the force's database. It turned out that the witness had been mixed up in previous, unrelated police investigations, and the search generated a list of alternative addresses he had been spotted at, mentioned in witness statements.

From this list, Williams was able to track him down. "The trail on this person had gone cold, but we found him within a few hours using ...