‘How much do you want me to explain about location, Boss?’ she asked, looking at Moss and Peterson and the other new members of the team.

‘Imagine we know nothing. We don’t live near Hayes. We’ve never heard of Jessica Collins. We are all hearing this for the first time… And remember,’ Erika added standing and addressing the incident room. ‘There are never any stupid questions. If you don’t understand something, shout.’

She sat back down, and DC Knight moved to the giant four metre square map on the back wall,

‘Okay so this map covers an area of twenty miles from top to bottom. In the centre is central London, and the bottom of the map, down south is the Kent borders, and here we are in Bromley Cross,’ she said indicating a large red cross on the map. ‘And we’re 2.6 miles from Hayes village. It’s a popular commuter belt village, lots of people who live there work in the city of London. It takes thirty minutes to get into the centre of London by train, and it has a higher than average population of retired people. Property prices are high, and it’s a predominantly white demographic area…’

Knight then nodded to DC Temple who turned off the lights. She moved back to a laptop activating the projector, which shone a larger scale map on a blank square of whiteboard. Knight moved to one side of it and went on,

‘This is a larger scale map of Hayes Village. You can see the high street here in the centre, and where the houses thin out to the north it becomes Hayes Common. The common is an area of woodland and heath, crossed by bridleways and footpaths. It’s one of the largest areas of common land in Greater London, at 225 acres. There are multiple access points to the common that can be accessed from Baston Road, Baston Manor Road, Five Elms Road, Croydon Road, Prestons Road, Warren Road, West Common Road and Commonside. At its southern end is the disused quarry where Jessica’s remains were found. The quarry was created between 1906 and 1914, when sandstone was excavated. Over the years it has twice been filled and cleared; during the Second World War there was an army base at Hayes common and anti-aircraft guns. In 1980 the quarry was cleared for the second time by archaeologists as part of a wider dig looking for Bronze Age relics. After this, it was left to fill with water. Bromley council twice put forward applications to have the quarry used for commercial fishing, but on both occasions the idea was overturned as the common is a site of nature conservation interest, and is protected.’

She paused and moved to the other side of the map, the projection of the roads playing over her tired face like arteries.

‘I’ll now move on to the timeline of events leading up to the disappearance of Jessica Collins. She lived here with her family in 7 Avondale Road, which is less than a mile from the Hayes Quarry, the closest entrance being here on Five Elms Road. You can see the houses on Avondale Road are all detached with large gardens. It’s an affluent area. On Saturday 7th August 1990 at 1.45pm, Jessica left her house to go to a birthday party for her school friend, Kelly Morrison, who lived at number 27 Avondale Road. It was only a short walk of around five hundred meters, but she never arrived. The alarm wasn’t raised until over two hours later, just after 4pm, when Marianne Collins arrived at 27 Avondale Road to collect Jessica, and saw she wasn’t there.’

She nodded at Temple and he went to the laptop and a Google Street view image appeared,

‘Here’s a view from the top of Avondale Road where it branches off a main road.’

The Google Street view blurred forward in bursts, the image moving past the houses on Avondale Road. ‘You can see that the houses are all large, two of three storeys. They’re all set back from the street and many of them have high hedges, trees… Here we are passing 7 Avondale Road, the Collins house… and we’re moving forward to 27 Avondale Road. I’m trying to get hold of images of the street from 26 years ago, but from the witness statements I’ve read. As is today, it wasn’t possible to see the street from inside most of these houses.’

The Google Street view surged forward past better-appointed houses. A postman was frozen mid-walk, his face blurred and his hand deep in his mailbag. Further along, a woman was emerging from one of the driveways with a small dog. From the back she had short curly blond hair.

‘Okay, now you can see that Avondale Road curves sharply to the left where it becomes Marsden Road.’ She pointed to a large manor house painted a buttery yellow with a grand pillared entrance. ‘This is now, The Swann Retirement Village, a nursing home, but 26 years ago it was used a halfway house for convicted sex offenders. Its existence wasn’t made public, and it only came to light shortly after Jessica’s disappearance. One of its residents, Trevor Matthews was the main focus for the original investigation. Photographs of Jessica were found in his room on the top floor. And the Matthews house could be seen clearly from his window. He was also spotted by a neighbour hanging around outside their house on the afternoon of August 5th, on the 6th around the same time and on the morning of the 7th. He was arrested on the 10th August. He was kept in custody for questioning, but no evidence, beyond photos he had taken of Jessica was found to link him to her disappearance, ’

‘But now we have a body,’ said John.

‘We have Jessica’s remains, but there is virtually no forensic evidence after twenty-six years underwater,’ said Erika.

Knight went on,

‘All members of Jessica’s immediate family have an alibi. Marianne and Martin were both at home with Toby. An elderly neighbour and her husband popped in for coffee at around 3.15pm, a Mr and Mrs O’ Shea now deceased. They stayed for forty-five minutes until Marianne left with them to go to collect Jessica. Their oldest daughter Laura was a two hundred and forty miles away on a camping trip with her boyfriend in the Gower Peninsula in Wales. They’d left early the day before.’

She looked at the room.

‘The results of a door-to-door weren’t helpful, most neighbours were out and those who were in had strong alibis. As you saw in the Google Street Map, most houses are blind to Avondale road, we have a two hour period where anything could have happened. There were few tradesmen; there is no post on a Saturday afternoon. Back in 1990 very little of the area was covered by CCTV. No buses travel down Avondale Road.’

A silence fell over the room for a moment before Temple put the lights back on. Erika moved to the front and stood by the map, now faint under the strip lights.