(CNN)A "dangerous and predatory" former English National Ballet principal dancer has been found guilty of sexually assaulting his teenage students.
Yat-Sen Chang, 49, was on Tuesday convicted at London's Isleworth Crown Court of 12 counts of sexual assault and one count of assault by penetration, the Crown Prosecution Service (CPS) said in a statement sent to CNN.
Chang assaulted the four women, aged between 16 and 18 at the time, through inappropriate massages as he worked as part of the English National Ballet and Young Dancers Academy, the CPS said.
The crimes took place from December 2009 to February 2016, and a police investigation was opened in April 2016 after a victim reported the abuse.
In the UK, victims of sexual offences receive lifelong anonymity from the moment they make an allegation.
During one incident, Chang asked a victim to lie down and began massaging her leg before moving his hands higher up, the CPS said, adding that the victim became concerned and told him to stop.
In another incident with the same woman, the CPS said, Chang led the victim to the men's changing area, got undressed and tried to hug her.
"Yat-Sen Chang used his position as a famed and trusted ballet teacher to groom and sexually assault teenage dancers under his training," Nahid Mannan, from the CPS, said.
"At 20 years their senior, Chang would have been well aware that his conduct was grossly inappropriate and predatory. Yet he used his power and influence to abuse and sexually intimidate his young victims," Mannan added.
Mannan said that, throughout the trial, Chang had claimed that, while he advised students to get massages or to stretch to help with tight calves, he didn't offer to massage students himself, and had only touched students to correct posture during lessons.
"However, the strong prosecution case which included evidence provided by the victims in pre-recorded video interviews, meant that the jury were able to convict Chang for his crimes," Mannan said.
The Metropolitan Police said in a statement Tuesday that Chang was found unanimously guilty of 13 counts and acquitted of one count.
Detective Constable Helen Larson, from the Met's West Area Child Abuse Unit, said: "Chang is a dangerous and predatory individual who targeted these young victims. He abused his position of trust and power to prey on them when they were most vulnerable."
Judge Edward Connell told Chang his offending "escalated in seriousness" and said the dancer faces a "lengthy custodial sentence," PA media news agency reported. He will be sentenced on June 18.
Chang is Cuban and lives in the German city of Kiel, PA said. He joined the English National Ballet in 1993 and was a principal dancer until 2011, where he danced in "The Nutcracker," "Coppelia" and "Sleeping Beauty," according to his Theater Kiel profile.
Chang said during the trial that he had "no idea" why the allegations were made against him and denied touching any of the complainants in an inappropriate or sexual way, PA reported.
CNN has attempted to contact Chang's representatives and has contacted the English National Ballet for comment.
Following legal advice, the board of Theater Kiel has decided Chang will be "suspended immediately," a spokesperson told CNN in a statement. "The theater will be examining further steps," they added.