How many times did police officers interview the Yorkshire Ripper, Peter Sutcliffe? Often enough, you'd have thought, to make some sort of connection between him and the murder of 13 women between 1975 and 1981.
The Yorkshire Ripper case was a classic example of police disorganisation: detectives interviewed a quarter of a million people and took 32,000 statements.
Sutcliffe was interviewed nine times by five different police forces but it was not until after he was arrested by chance with a prostitute in a car, in possession of a knife and hammer, that the case was solved.
Lessons had to be learnt from the failures of the Yorkshire Ripper case. The police painfully acknowledged that serious mistakes were made because officers and detectives who spent hundreds of hours writing out reports of interviews often could not find them again because of a poor filing system.
Connections were not made between Sutcliffe and the murders. He was allowed to go free time and time again.
A computer-based system, known as Holmes 1 because it was named after Sherlock Holmes, replaced the paper system a few years after Sutcliffe was convicted.
"It was a bloody good system," says Doug Stuckey, of the computer company Unisys, which has spent the last four years and up to £35 million developing its replacement, Holmes 2.
The original computer system was really an electronic filing cabinet. It was not used by every police force in Britain and three different versions of the system were in operation at the same time. It was also difficult for the systems to "talk" to each other.
Holmes 2, which is an improvement on the original and has the potential to link all the police forces into an internal information "Internet", will be formally launched today. "We wanted to do better than the original," Mr Stuckey explains. "With this system all the forces will be using the same one so, for example, an officer in Merseyside can search for information on a crime or suspect provided by Yorkshire police."
In a process known as diagramming, which aims to apply logic to pathological crimes, the new system will be able to build up networks of connections from the huge amounts of data involved in major crime investigations.
It's a bit like building up a profile of the suspect. The computer can quickly analyse a suspect's telephone records, for example, and group telephone numbers together so that a picture of when and how often a suspect is calling a particular contact. The details of politically sensitive or anti-terrorist investigations can also be kept secret within police forces with the help of multi-layered security gateways that have been incorporated into the computer system.
A degree of "intelligence" has been built into the computer, so it is able to learn connections and associations within thousands of pages of information because it is able to read an entire investigation as one document.
"It spots associations, even if you haven't asked questions, and the suggestion button lights up and says to you, "Did you know that suspect X, Y and Z drink in the Dog and Duck every Friday night?" Mr Stuckey says.
"But it does nothing more than make a suggestion. It won't store the suggestion and it won't provide an audit trail. So everything still has to be manually confirmed and checked."
Another feature is a casualty bureau, which means the computer will be able to collect information on a national disaster, such as the Paddington rail crash, and make connections to identify missing persons. Using information provided by individual police officers the computer can link a handbag found at the crash site with an injured woman admitted to a nearby hospital and prompt another officer to contact her family.
So far, 25 - about half of the British police forces - are linked to Holmes 2, and the RUC is expected to go online next year. Small forces can expect to pay up to £250,000 to install the system, with larger ones, such as the Metropolitan Police, paying several million pounds for Holmes 2, and Unisys is likely to make a bid for the contract if the Garda decides to adopt a similar system.
There are potential difficulties, however, because information can only be shared if individual forces agree to release it onto the Holmes system. "The technology is willing, but the culture is weak," says Mr Stuckey, who admits the system will realise its full potential only if police forces improve their ability to share information.
The Macpherson report into the investigation of the murder of Stephen Lawrence condemned the disorganisation among officers in the early stages of the case. Crucial information was not shared until it was too late and computers were not used properly to record the facts of the case. If Holmes 2 can end these problems it will be seen as a success.