Forensic science service plays vital role in helping Metropolitan Police convict notorious rapist

Forensic science service plays vital roleCrucial evidence analysed by the Forensic Science Service played a key role in helping the Metropolitan Police Service (MPS) to solve their biggest ever rape investigation and finally bring a dangerous offender to justice after almost 20 years.

Hundreds of items were examined and a range of forensic techniques used by scientists as they assisted the MPS every step of the way in the hugely complex Operation Minstead enquiry.

DNA, fibres and toolmarks all played a key role in proving Delroy Grant’s involvement in a series of rapes, indecent assaults and burglaries across the South London and Surrey area between 1992 and 2009.

By the time Grant was arrested, Operation Minstead had become the largest and most complex rape investigation ever undertaken by the MPS and the FSS.

Over the 17-year period, Grant managed to evade witness descriptions by covering his face and striking in the middle of the night. He disabled the lights by either switching the electricity off at the meter or unscrewing light bulbs.

Despite these lengths, the same DNA profile was repeatedly discovered at scenes, which bore the distinctive hallmarks of the Operation Minstead offender. The profile was recovered from a total of 12 scenes over the offending period. The first profile was found by the FSS at the scene of a rape in Shirley, South London in 1992, in the infancy of DNA testing. It was searched against suspects in the case, with no success. The profile was later upgraded from an early SLP (Single Locus Probe) profile to an SGM profile compatible with the National DNA Database, launched by the FSS in 1995. It immediately hit against a DNA profile, which had been found at an attempted rape scene in Surrey in 1998. This scene to scene hit flagged up a linked series of offences to police, but at this time there was no match to an offender on the database.

The same DNA profile continued to be found at scenes matching the mystery offender’s modus operandii throughout the 1990s and 2000s. DNA samples were recovered from the victims as well as items including a scarf, a discarded glove, a screwdriver and a drinks bottle. FSS experts were even able to obtain a DNA profile from semen in a bowl of water which was used by the offender to wash a victim’s nightdress at an address in Croydon in 1999. However, despite the exhaustive scene searches and scientific expertise, the offender was never arrested for any other crimes during this period and thus his DNA profile was not loaded to the Database.

On 15 November 2009, though, police arrested Delroy Grant following a police operation. A DNA sample was taken from him and sent immediately to the FSS. It arrived at the lab in the early hours of a Sunday morning, but aware of the significance of the development and the imperative for the fastest turnaround possible, the team pulled out all the stops. The sample was fast tracked and a statement was given to police saying that Grant had been matched to three of the Minstead scenes within just eight hours. This swift service meant that Grant could be charged whilst he was still in custody.

FSS Senior Forensic Scientist Ray Chapman has worked on the case since the very first recorded offence in 1992. He said there was a feeling of jubilation in the laboratory when the DNA match came through.

“We had done an enormous amount of work on this case over the years and there was a real feeling of frustration that we had never been able to match the DNA” he said.

“We were obviously aware that the police were hopeful that this was finally their man but it was almost a feeling of disbelief when we saw that his profile matched the profile found at so many of the scenes.

“For the sake of consistency, only two Reporting Officers with the help of three or four assistants have worked directly on this case. However over the years more than 100 scientists have contributed in different ways, mostly doing DNA testing, and we have assisted police forensically in every way we could. We had the DNA profile from the outset of the investigation and we always believed that it was a matter of time before the offender was found.”

As well as the vital DNA work, throughout the investigation the FSS used other techniques to find links between Minstead scenes and between the scenes and the unknown offender.

Grant’s modus operandii was to remove windows from properties to gain access and in doing so he frequently left tool marks on the window beading. Comparison microscope work carried out by experts at the Lambeth laboratory showed conclusive links between six offences in 1999 and a further one in 2002. Corresponding unique damage features could be seen within the marks at every scene. Marks from an offence in 2009 were linked to a screwdriver found at a scene a few weeks later. A DNA profile on this screwdriver belonged to the Minstead rapist. A case opener recovered from Grant’s vehicle after his arrest was also linked to tool marks from a recent offence.

Fibres evidence also played a corroborative role in the case. Fibres were found at the scene of a burglary in Bromley on September 7 2004, stuck to strips of window beading. In line with the Minstead Rapist’s usual technique a window had been removed to gain access to the home of an elderly victim. More than 4,000 fibres were stuck to glue surrounding the beading, which could only have been left by the person who had removed the window.

During the police investigation a black glove was also found under a bush several doors down from the property. An expert under a high power microscope examined fibres from the beading and they were found to be a match to the fibres from the glove. Further testing confirmed the match and that the fibres were of the same type of acrylic as the gloves.

DNA testing of the glove also carried out by the FSS located a mixed DNA profile, which was likely to have originated from one man and one woman. Following Grant’s arrest further analysis revealed that it was a billion times more likely that these profiles belonged to Delroy Grant and his girlfriend than to two other unrelated people.

Ray Fysh, the Specialist Advisor who worked with the Metropolitan Police throughout the investigation said that the FSS’ dedication to helping the Met catch the Operation Minstead rapist never wavered.

“We have worked closely with the Met and done everything we can forensically to support their enquiries over the years,” he said.

“The FSS was able to offer a cohesive service across all forensic disciplines to find key links between offences and to link Grant to the crimes.

“It is also important to say that we have been quickly able to eliminate people from enquiries thanks to mass DNA screens and fast-tracking samples. Our work is always about exonerating the innocent as well as finding the guilty. We are very pleased we have been able to assist in bringing this investigation to a successful conclusion.”

Delroy Grant was found guilty of 18 counts of burglary, three counts of rape, one count of attempted rape and seven counts of indecent assault on 24 March 2011 following a trial lasting three weeks.