Naked on the tarmac, underneath a yellow forensic tent, lies the body of Carl Beatson Asiedu. His mouth is open and, while one eye is closed, the other stares vacantly. The 19-year-old is yet another victim of London's knife-crime epidemic. Stabbed following an argument outside a nightclub, Carl was found dying in the back of a car when his friends, who were rushing him to hospital, ran a red light.
As his life ebbed away on the streets of Waterloo, responsibility passed from the medics who had tried, but failed, to save him to the Metropolitan Police's Murder Investigation Team 9 (MIT9), whose job it is to ensure that his death will not go unpunished. Based in Sutton, MIT9 is one of the Met's 24 homicide teams. This week they are on call, which means that at any minute the phone could ring with news of a death and they will be first on the scene.
Carl's murder is one of a handful of open cases that the team is currently working on. The murder of Andrew Cunningham, a convicted paedophile who was murdered and mutilated in his caravan in Wandsworth, is another. And the case of Ben Gardner, an IT worker beaten to death after he confronted three men who stole his girlfriend's Hallowe'en hat, is a third. As one of three on-call murder teams in London, MIT9 will be the first called to any new murder in their patch – the south of the city. But while they wait, there are other murders to solve.
Carl was murdered in August last year. One of the men whom detectives believe killed him has fled to Nigeria, and officers are building their case in the hope of having him extradited. In the Incident Room, DC Chatfield takes a DVD labelled 'Operation Elk Springs' – the investigation's codename – and loads it into a laptop. It shows a minute-by-minute account of the last moments of Carl's life. He and his friends leave Club Life – the nightclub in Vauxhall where he disc-jockeyed that evening – and walk towards their cars. Minutes later they are followed by a large group and, while the footage does not show the murder, it is here that officers believe Carl was stabbed.
The short sequence, made up of footage from three different security cameras, was painstakingly compiled by DC Chatfield. He explains: "I watched hundreds of hours of footage. I was in from 8am until 11pm every day for two weeks, just watching clip after clip. Some nights I wouldn't realise the time until I checked my watch."
It was monotonous, but murder-squad detectives are at pains to highlight the importance of CCTV. To make his point, Detective Inspector Chris Le Pere points to CCTV footage of a particularly shocking murder. The video shows three boys – two white, one black – walking back to their car after a night out. On the way they come across their two victims. Without warning, one of the three throws a punch at one of the victims. As he falls to the floor, his friend tries to calm the situation. He is stabbed once, underneath the arm.
The wound punctures his heart and, off camera, the boy dies within 60 seconds. The other victim is forced to hand over his mobile phone and wallet while the knifeman stabs him. When the boy finally gets up, he is soaked in blood and staggers to find help. DI Le Pere says: "People complain about CCTV nation, and Big Brother watching them, but that case had no forensics and when we spoke to the lad who survived he was so confused that he was convinced they were attacked by a gang of six black men. Without CCTV we could not have solved that case."
Of course, most cases also rely on forensic evidence. One floor below the incident room sits the exhibits room. Here, three huge cages contain every piece of evidence gathered on the team's current jobs. Brown paper bags marked "POLICE EVIDENCE" contain items such as shoes, clothing and mobile phones. One, larger, bag contains a caravan door while on top of another cage is a child's bike.
"A typical job produces between 1,500 and 2,000 exhibits," says DC Darell Ayaydin. "We throw a lot of weight behind forensic evidence because while defendants and barristers might dispute what witnesses and police officers say, they cannot argue with science."
Each piece of evidence will be stored by the force for 30 years in an industrial warehouse in Birmingham – longer in cases that are never closed. "Nothing is forgotten," DC Ayaydin adds. "Whether you are a pimp, a prostitute or a princess, murder is murder and we put the same amount of effort into every case."
The internet is also used by the police in their murder investigations. Detectives will log on to social networking sites to gather intelligence on suspects. And it is surprising what they can come up with. "Criminals are mugs," says DC Darren Lovatt. "If I committed a crime, the last thing I would be doing is talking about it on the internet where lots of people can see it. The same goes for mobile phones. It is no great secret that police can check mobile-phone records, yet some people lie about whom they have been in touch with, even though they must know we can find out."
As if to illustrate the point, Detective Sergeant Danny Gosling and Detective Constable Murray Bannister decide to visit a potential witness in one of their cases. They have been told he witnessed a murder, but are not confident he will talk to them.
Holding up a printout from the man's Facebook page, they point out he is a member of a group called "I HATE POLICE". Sure enough, they return empty-handed. Problems with witnesses are not uncommon. In the case of Carl Beatson Asiedu, the detectives have been frustrated by some witnesses who are slow to return calls or attend meetings.
DI Le Pere explains: "There is a saying we use about witnesses that do not co-operate, 'their loyalty is to the living'. Even though their friend is dead they take the view that there is nothing they can do to bring him back so their loyalty now is to their friends, and sometimes even their enemies, who are still alive. It is frustrating, because you know that they may have evidence that your case needs."
It is one of the issues which DI Le Pere and DS Matt Flynn are keen to explain to Carl's parents when they visit their home in south London on a Friday evening. The family home is a shrine to Carl. Pictures of him adorn the walls while the mantlepiece is crowded with medals and trophies from his school days. Part counsellors, part avengers, the detectives have a dual role in these investigations, and can often be the focus of family frustration.
"I apologise that it seems to be taking a long time, but we have to be meticulous," DI Le Pere explains. "We have nearly 1,000 witness statements and have spoken to well over half the people in the club that night. I am always a positive person and I do not want to give you false hope, but the evidence we are gathering is very good."
Carl's parents say they are content with the investigation, but are also keen to tell the detectives about what they have suffered since their son died. "It is not an easy thing, but I have to deal with it," his father John says. "I always say that whoever has done this has imposed a life sentence of sorrow and pain on us and we have to deal with that every day. What they fail to realise is that when you kill someone, those left behind suffer more."
Hilda, Carl's mother, continues: "They have killed an innocent boy who has done nothing wrong. You can never understand unless you have been put in that situation. People can sympathise with you, but they can never know. Sometimes you are fine, but other times you just burst out crying." John has only one question: "When do you hope to charge somebody?"
The officers demur because they know they can do little until their suspect is extradited, and they do not know when or even if that will happen. Hilda's question is even more unanswerable. "Why did my son have to die such a horrific death?" she asks. As he leaves the house, DI Le Pere says: "The victim's family are exactly why we do this job. We need to get justice for them."
Back in the incident room, the murder squad's nightshift passes slowly when nothing is happening. Six officers are on duty, but this will drop to three – two constables and an inspector – at 2am. While some of the officers quiz each other on obscure laws ahead of their upcoming sergeant's exams, others use the time to catch up on paperwork.
As the television blares in the background, everyone waits for the Homicide Assessment Team mobile phone to ring – its ringtone is the first thing that alerts the detectives to a possible murder on their patch.
A popular prank, to break the monotony, is to ring the phone from across the room – a stunt particularly effective at the changeover point in a shift when arguments will break out about whose duty it is to take the call.
As the time ticks by, a curry is ordered from a nearby takeaway. Meanwhile, flicking through the television channels, an episode of the detective series A Touch of Frost comes on. "I bet he has plenty of murders," someone says.
Much of what the public knows of murder investigation comes from television, but the reality is rather different. While the on-air cases are solved in days, many real-life investigations take months, sometimes years. And while TV cops are snowed under with murders, the reality is, thankfully, rather different.
As 2am nears, the officers at the end of their shift settle down to watch Britain's only medal hope in the Winter Olympics. But as Amy Williams hurtles towards a gold on her skeleton bob, DS Matt Flynn is preoccupied with the Carl Beatson Asiedu case. As he compiles evidence files which will be sent to the Crown Prosecution Service for consideration, he says: "This is a profoundly sad case. There was just no reason for it; it was a totally pointless murder over some silly argument."
There is an added incentive for the team to solve the case. As far as the officers in MIT9 are aware, there has never been a successful extradition between Britain and Nigeria. "Of course it would be nice to be the first," DS Flynn says. "But the real reason we want to solve cases is because we love this job and we love the work. On a good day, when we get the right results, it is great. But when we get the wrong result it is deflating and the whole team will feel it. It is not a nice feeling, so that is why we are meticulous with everything."
Tomorrow: On call with the Sutton murder squad