The DNA of a man accused of inappropriately touching a murdered teenager’s body instead of alerting police may have been present on her body before her death, a forensic biologist has said.

Stephen Corrigan, 45, is on trial accused of discovering Amber Gibson’s body between November 26 and 28 last year but instead of alerting police, he is alleged to have inappropriately touched and concealed her body.

The 16-year-old’s body was discovered on November 28 2021 at Cadzow Glen in Hamilton, South Lanarkshire.

Her brother, Connor, is also on trial at the High Court in Glasgow accused of murdering and sexually assaulting Ms Gibson, who was also known by the surname Niven.

Corrigan’s defence agent, Rhonda Anderson, cross-examined forensic biologist Alana Gunn on Wednesday.

The court had previously heard from Ms Gunn that Corrigan’s DNA was “widespread” on Amber’s body, spanning 39 areas, including her buttocks, breasts and pubic area, with the forensic biologist estimating it came from “direct contact”.

However, following questioning from Ms Anderson, Ms Gunn said she could not “exclude” the possibility that his DNA was on the teenager’s body by secondary transfer.

Ms Anderson put to Ms Gunn, if Ms Gibson had slept naked inside a sleeping bag that had Corrigan’s DNA on it before her death, that could account for why his DNA was on her body.

We cannot tell you exactly what time the DNA was deposited

Ms Gunn replied: “If there was a significant amount of DNA in the sleeping bag then I couldn’t exclude that, no.”

Ms Anderson said: “As I understand it, your position from your evidence is that it could be that Stephen Corrigan’s DNA deposited on Ms Niven’s body could have been deposited before she went to the park (Cadzow Glen).

“Should the ladies and gentlemen on the jury understand that you are unable to exclude that his DNA was deposited on Amber Niven’s body before she went to the park and before she died?”

Ms Gunn replied: “We cannot tell you exactly what time the DNA was deposited,” before adding evidence did not say whether it existed on her body before or after her death.

Both Corrigan and Gibson deny all charges against them, with Ms Anderson lodging a special defence of alibi on her client’s behalf.

Gibson is also accused of removing his sister’s clothes and repeatedly inflicting blunt force trauma to her head and body on November 26 2021.

Prosecutors allege he compressed the 16-year-old’s neck with his hands and strangled her with the intention to rape her.

Her faces further charges of attempting to defeat the ends of justice by disposing of bloodstained clothes and calling the children’s home where his sister lived and pretending she was alive.

He also faces a charge of attempting to pervert the course of justice by telling police he had argued with his sister on the evening of November 26 before going to someone’s home.

The trial, before judge Lord Mulholland, continues.