Police investigating claims of historic sexual abuse at two music schools are considering extradition proceedings against a former violin teacher who is living in the United States.
Greater Manchester Police want to question Chris Ling, 56, as part of their investigation into abuse allegations at Chetham's School of Music and the Royal Northern College of Music (RNCM).
Last February, the Guardian newspaper reported claims from 10 women that Mr Ling abused them in the 1980s while he was a freelance teacher at Chetham's in Manchester.
Mr Ling moved to the United States in the early 1990s and runs a talent management agency from his Los Angeles base.
He has refused to comment on the allegations when confronted by reporters at his home.
A spokesman for Greater Manchester Police said: "A file of evidence has been compiled and submitted to the Crown Prosecution Service (CPS) in relation to complaints against Chris Ling.
"Mr Ling has been invited to be questioned in relation to these matters but to date has failed to return to the United Kingdom to allow this process to take place.
"As such, we have been left with little alternative but to consider extradition proceedings and are working closely with the CPS as part of this process."
Four men have been arrested as part of the investigation and are currently on bail pending further inquiries.
Last May, Greater Manchester Police said more than 30 women had made complaints that they suffered sexual abuse from classical music teachers.
It added that 10 key suspects had been identified in the wide-ranging inquiry called Operation Kiso.
Those suspects either taught at Chetham's, the RNCM or privately.
Some 39 individuals had been investigated in the operation, of whom five are dead, according to GMP.
The allegations came in the fall-out from the high-profile sex abuse trial last year of Michael Brewer, the former music director at Chetham's.
Brewer was jailed for six years in March after he was found guilty of indecently assaulting ex-pupil Frances Andrade, 48, more than 30 years ago when she was 14 and 15.
Mrs Andrade killed herself at her home in Guildford, Surrey, a week after giving evidence against him.
The trial heard historic allegations that sexual activity between teachers and pupils at Chetham's was not uncommon.
Violin teacher Wen Zhou Li, 57, a professor at the RNCM and a former teacher at Chetham's, was held last February on suspicion of rape.
The Chinese national, who lives in Cheshire, joined RNCM and Chetham's in 1996 as violin professor and principal violin tutor.
Renowned double bass teacher Duncan McTier, 58, was arrested at his home in London in May over allegations of sex abuse against a woman in her 20s in the mid-90s.
The alleged offence is said to have taken place while the victim was a pupil at the RNCM in Manchester.
Mr McTier was a part-time teacher in his specialist field at the Manchester college between 1984 and 1996.
He is a professor of double bass at London's Royal Academy of Music and holds similar positions at the Zurich University of the Arts and the Queen Sofia College of Music in Madrid.
Internationally acclaimed conductor Nicholas Smith, 65, from Macclesfield, Cheshire, was held in July on suspicion of committing sexual offences against a 15-year-old girl in the late 1970s while she was a pupil at Chetham's.
According to his website, Mr Smith has worked around the world and was music director of the South Carolina Philharmonic between 1993 and 2007 and the Kuopio Symphony Orchestra in Finland from 1982 to 1990.
He has performed as a conductor in Spain, Poland, Germany, France, Northern Ireland and England, including for the Royal Philharmonic Concert Orchestra.
He also became principal conductor of the Northern Chamber Orchestra at the age of 22 and has conducted many productions at the Buxton Opera Festival, said his website.
Former Chetham's teacher Malcolm Layfield, 61, was arrested in August on suspicion of three historic rapes against three females, two aged 16 and one 18, between 1980 and 1991.
Mr Layfield, also a former head of strings at the RNCM, was re-arrested in October on suspicion of the rape and indecent assault of a woman when she was aged between 18 and 21.