Aqsa Mahmood, 20, who is the daughter of a successful Glasgow businessman, is suspected of helping to recruit three London schoolgirls to the Islamic State terror group.
The woman, who was educated at private school, is alleged to have used Twitter to encourage acts of terrorism and is accused of urging British Muslims to carry out “another Woolwich”; a reference to the brutal murder of off-duty soldier Lee Rigby by extremists in May 2013.
Giving evidence to the Commons Home Affairs Committee, Mark Rowley, Assistant Commissioner at the Metropolitan Police, told MPs: “The Scottish woman who has been reported overseas, that case is well-advanced in the work that is going on in terms of potentially prosecuting her if she ever returns.”
Mahmood, from Pollokshields, is suspected of being involved in the disappearance of 15-year-olds Shamima Begum and Amira Abase and Kadiza Sultana, 16. The teenagers, from Bethnal Green, East London, last month flew from Gatwick Airport to Istanbul and crossed into Syria also to become jihadi brides with Isis militants.
Mahmood’s family’s solicitor Aamer Anwar said they were “full of horror and anger that their daughter may have had a role to play in the recruitment of these young girls to Isis”.
But he was critical of Mr Rowley, saying: “It is extremely disturbing that Assistant Commissioner Mark Rowley should use the Select Committee to publicly announce their work as being ‘well-advanced’ in terms of prosecuting Aqsa Mahmood.
“One would hope that the Crown prosecution would have concerns on the right to a fair trial and anything being done to jeopardise due process; unless the Met believes that no longer applies in the UK.”
But Mr Anwar said there were more serious questions raised in relation to the case of the London schoolgirls.
“Aqsa’s family have repeatedly said their daughter was being monitored by the security services and police for over 15 months. If she was responsible for the recruitment and radicalisation of young girls, then why did the security services not share that information with the families before it was too late?” he asked.
The family solicitor suggested that Mr Rowley should perhaps have used his time before the Committee “more usefully by answering that question rather than grandstanding”.
Mr Anwar added: “As for Aqsa’s family, they were advised by my office some time ago of the likelihood of prosecution if she were to return to this country.
“They are deeply ashamed of their daughter and any role she may have played in the recruitment of these young girls but she is still their daughter and they would much prefer her back in Scotland alive than for her to die in Syria.”
A spokesman for Police Scotland said “Our investigation into the circumstances surrounding Aqsa Mahmood continues to be a live, ongoing inquiry and it would therefore be inappropriate to comment further.”
A Crown Office spokesman said: “This is a live investigation. It would not be appropriate to comment.”
Mahmood’s parents contacted the police to report her missing in November 2013. It was subsequently discovered that she had travelled to Syria, where she is believed to have married an Isis fighter.
At Westminster, MPs were told how the three London schoolgirls were thought to have funded their flights from Britain to Turkey, costing more than £1000, by stealing jewellery from their relatives.
Asked how they had raised the money, the Assistant Commissioner said: “We think it’s linked to theft from families…taking jewellery from one of their family members.”
In earlier evidence, relatives of the three girls demanded an apology from the Met for failing to hand letters from the police directly to them, warning parents about how a 15-year-old pupil had run away to Syria in December.
Sir Bernard Hogan-Howe, the Met Commissioner, apologised for failing to communicate more directly with the families of the three schoolgirls but insisted there was nothing more the force could have done to stop them from leaving.
“In hindsight, we now know these girls were planning to go and neither the family, the police, the school nor anyone else realised that,” he said.
Earlier, Amira’s father Hussen Abase, Khadija’s cousin Fahmida Aziz and Shamima’s sister Sahima Begum said there were no indications the girls had been radicalised.
Ms Begum noted: “My sister was into normal teenage things. She used to watch Keeping Up With The Kardashians.”
Elsewhere, Prime Minister David Cameron insisted no one institution should become a “scapegoat” for the schoolgirls’ disappearance, saying “everyone has a role to play” in preventing Britons from joining Isis, including politicians, parents, communities and schools.