DNA discovered on the clothing of an autistic 14-year-old girl "probably" belonged to one of two Afghan migrants accused of sexually assaulting her on a train, a court has been informed. Baryalai Rahimi, 25, and Mirebadurahman Sadat, 29, are alleged to have followed the runaway teenager onto a London-bound train from a station in rural Kent on February 5.

Both Rahimi, of Southall, west London, and Sadat, of Cricklewood, north-west London, deny a total of 20 charges, which include multiple counts of sexual activity with a child. Jurors at Inner London Crown Court heard that Rahimi is accused of raping the girl three times in the train's toilets, while Sadat allegedly assaulted her twice.

During the trial, forensic expert Kassandra Harris was questioned about DNA found on the victim's clothes. Sebastian Cox, defending Rahimi, asked if skin cells shed from the body can be left on surfaces. Ms. Harris confirmed this, stating that DNA can be recovered from just a few skin cells.

When questioned about whether penetrative sex would lead to DNA findings, Ms. Harris explained that the presence of female DNA within the vagina could potentially overwhelm any male DNA, making the results inconclusive regarding the occurrence of penetration itself. She confirmed, "Yes, you can't say whether or not it has."

Ravindra Chandrapala, defending Sadat, questioned Ms. Harris's qualifications, noting she had not published scientific papers or contributed to books. Ms. Harris stated her expertise is certified by courses accredited by the United Kingdom Accreditation Service. Mr. Chandrapala pressed, asking if she could definitively state Mr. Sadat's DNA was present. Ms. Harris responded, "I can say that my findings support the fact that his DNA was present."

The court also heard a playback of the victim's police interview, during which she stated that other passengers on the busy Southeastern service were preoccupied with their phones and not paying attention to her. Rahimi, in a prepared statement to police, claimed he believed the girl was 17 or 18 and that she was the one who initiated the encounter, which he described as consensual. Sadat denied the accusations, stating, "I did not do what I am accused of. I deny these offences."

Rahimi faces three counts of rape, two of sexual assault, one of assault by penetration, and six alternative counts of sexual activity with a child. Sadat denies two counts of assault by penetration, two of causing a person to engage in sexual activity without consent, and four alternative counts of sexual activity with a child. The trial is ongoing and is expected to last three weeks.