Rashid Musa, 22, raped a woman cleaner and a 16-year-old schoolboy within a 24-hour period and police believe there are more victims who have been afraid to come forward.
Musa, the Old Bailey was told, had fallen through the deportation net because of confusion about his nationality and because of a lack of resources.
Judge David Radford warn- ed him he faced a life sentence after being found guilty of two rape charges, one charge of attempted rape and two offences of stealing.
The court was told Musa arrived in Britain in 1992 from Brazil. He had a ticket to Kenya but on his arrival at Heathrow, claimed to be Somali and asked for asylum. In July 1994, he committed a serious sexual offence on a 15-year-old girl and was sentenced to 18 months' youth custody in January 1995.
In December 1995, a judge at the Inner London Crown Court recommended Musa be deported after serving an 18-month sentence for a burglary offence. He was served with deportation papers in Doncaster prison on June 18, 1997, but was released on June 23 after his lawyers served the Home Office with a writ saying that he would appeal and that he was being wrongly detained.
The judge was told that the appeal was dismissed by 16 October 1997 and the deportation order could have been implemented by 20 November 1997. But he was not sought, detained or deported.
By February, he attacked the 46-year-old woman cleaner in a central London office block. The next day, he raped the schoolboy in a train lavatory.
Judge Radford said: "Whilst he was at liberty, these offences were committed. I certainly want to know why that was - why there were delays in implementing these matters.
"I am considering whether it is my public duty to pass a life sentence in this case."
He remanded Musa in custody and adjourned the case until November 6.
Scotland Yard appealed for other victims to come forward. Det Insp Jim Dickie said: "It is my belief these were not isolated offences."
The Home Office said the immigration minister had ordered an urgent report on the case from the Immigration Service.Reuse content