On 13th November 2015, one-hundred-and-thirty people were murdered in Paris. It was one of Europe’s worst terrorist attacks, and, like all of the terrorist attacks that went before it, it made us feel less safe about the world we live in.

We rely on the police and the security services and we expect them to apprehend suspects of mass murder and terrorism quickly.  So why did it take the police four months to find Salah Abdeslam? After all, we live in an age of mass surveillance where billions are poured into programs just to keep track of us, don’t we?

Salah Abdeslam was identified fairly early on in the police investigation. He and his brother had hired cars that were used to transport the attackers to and from the attack sites; he had booked hotel rooms in Paris used by the attackers before the attacks; and his DNA was found in these same hotel rooms.

Salah’s brother, Ibrahim, blew himself up outside the Comptoir Voltaire cafe during the attacks. He injured three people, but killed only himself.

It seems increasingly likely that Salah actually backed out of becoming a martyr like his brother.

While the massacre was still ongoing inside the Bataclan Theatre, Salah purchased a SIM card from a shop in Paris and made a series of desperate phone calls to friends and associates in Belgium asking them to come and collect him. He wandered the streets of Paris for several hours while he made the calls. A suicide vest was found abandoned in one of the areas that Salah had roamed after the attack. Eventually two friends from his home town came to collect him and drove him back to Molenbeek in Belgium. 

Immediately after the attacks, Emergency Powers were enacted in France which gave the police the right to search properties without first obtaining a warrant to do so. In the three days following the attacks, French police searched over two hundred premises.

By the 18th November, just five days after the attacks, Abdelhamid Abaaoud, widely seen as the mastermind of the Paris attacks, was traced to a flat in St Denis, Paris.

A subsequent security operation killed him.

So why, then, did it take a further 119 days to find Salah Abdeslam when it was clear that he had been taken back to Molenbeek, Belgium immediately after the attack? 

The former wife of Ibrahim Abdeslam has described him as “a jobless layabout who smoked cannabis 'all day every day', never went to the mosque and had spent time in prison.” Descriptions of Salah and his life are little different. So we are hardly dealing with terrorist masterminds here, are we? These aren’t globe-trotting international experts who are masters in disguise that can outwit multi-skilled police and security services, are they?

Electronic surveillance is, by and large, the main sort of surveillance that our security services do. We all have a regular digital footprint and leave electronic traces wherever we go. Once they have your mobile number(s), IP address(es) and bank account/credit card details, they can pretty much follow you without ever leaving their office if they have the right authorisations in place.

Therein lies part of the problem. When a suspect returns to his roots, into a community where he has longstanding relationships, in an area where he grew up, amongst people who are willing to help him - he can disconnect from his normal digital footprint by not using any of his normal communication methods or contacts.

When he has associates who will willingly do all of this on his behalf while harbouring him – all the clever, office-based, electronic surveillance is useless.

The police and security services were therefore forced to go back to the basics of knocking on doors, talking to people and using their detective skills, contacts and intuition to uncover where this man was hiding. And this is where closed communities like Molenbeek cause most of their problems. 

Be it in Molenbeek, Belgium, or Beeston in West Yorkshire where the 7/7 bombers grew up - long standing, familial relationships knitted into the very fabric of the area, mean that police stand little chance of getting that early piece of intelligence that will lead them to the right door.  

We faced the same problems when we investigated the 7/7 bombers in West Yorkshire. For many, the laws of the land came a distant last place after neighbourhood bonds, familial ties, ancestral dues and criminal fraternities.

Unlike France, Belgium didn’t enact emergency powers that would have meant perhaps every door in Molenbeek being kicked in by the police within a few days in the hunt for Abdeslam. Belgium has a much softer approach to its community. Search warrants requiring evidence are needed to enter and search premises. Even then, they can only be undertaken during normal daylight hours.

Many will trumpet the gung-ho approach of President Hollande and his emergency powers for the speed in which they captured and then killed Abdelhamid Abaaoud. The same people will deride the Belgians for their softly, softly approach and blame this for the 119 day delay in catching Abdeslam, in the very community where he grew up.

Let me ask you this - how did the Belgian police find Abdeslam, alive? It wasn’t from someone sitting in an office using electronic surveillance on a digital footprint. It was good, old fashioned, detective work - banging on doors and talking to people. Making friends. Building trust and making their presence felt. They traced Abdeslam with the help from the local community who, by and large, wouldn’t have wanted this man living amongst them. There may also have been an element of luck and the right person coming forward at the right time - but, they found him, alive.

One thing is for sure – closed communities are a problem – they’ve played a part in helping grow the Abdeslam brothers and have now played a part in harboring one after he committed the most hideous of crimes. But they may also have been part of the answer – because it appears that someone may have aided the manhunt with a tip off.

As we move further and further away from local policing with increasingly centralised functions that rely on electronic mapping, facial recognition, electronic surveillance and internet based reporting methods, I can’t help getting the feeling that we are getting further and further away from solving these problems.

Historically, we disconnected from many of these communities.  Today we need local policing with officers that have good local knowledge about who the trouble makers are, know where to go to find answers and  know how to put the information gathered from our myriad of computer systems into context. 

Part of the problem in tracing criminals in closed communities is that many of the locals are more scared or mistrustful of the police than they are of these criminals. 

We need to gain the trust and respect of a local community. There must be the ability to knock on doors and find information out, which may lead to where suspects might be hiding. All the electronic surveillance in the world is useless if you don’t have the basics of policing in place. 

David Videcette is a former counter-terror detective who worked on Operation Theseus, the London 7/7 bombings investigation. His thriller, 'The Theseus Paradox', is based on real events and is available now at Amazon. The novel is helping to support the charity, The Police Dependants' Trust.