Nikka Allan murder trial: How DNA advances played a part in investigation into Sunderland girl's killing

DNA profiling in criminal cases was "extremely limited" in 1992, jurors trying 55-year-old David Boyd for murder were told.

Richard Wright KC, prosecuting, told Newcastle Crown Court: "The science was in its infancy and in the intervening 30 years the use of DNA evidence in criminal cases has become almost routine.

"More importantly, much more sensitive tests are now available that detect DNA in much smaller quantities."

Nikki's body was found in a derelict building in Hendon, Sunderland, on the evening of October 7 1992.

Mr Wright explained the development of Y DNA profiling, which looks at male DNA passed from father to son.

None of Boyd's DNA was found on Nikki's coat but traces that were a one in 28,000 match were found on her cycling shorts, and a one in 5,100 match on her T-shirt, the court heard.

"It is the clothing that her killer would have inevitably had to handle when forcing her into the building, picking her up inside and manhandling her," Mr Wright said.

Mass DNA screening of people in the area was carried out as part of a reinvestigation by police.

Mr Wright told jurors: "It is of course not possible to exclude every male person who may theoretically have been in the area on the night of the killing.

"However, of the hundreds tested, no DNA profile other than that of Boyd matches the male DNA profile obtained from the T-shirt and cycle shorts."