Plain-clothed police officers caught a sex offender who attacked a 13-year-old girl who was on the Piccadilly Line with her family during rush hour.
Undercover British Transport Police officers observed Abdulrizak Ali Hersi, 32, standing close to the doors after boarding at Green Park.
They watched as a family boarded at the next stop and Hersi sexually assaulted their teenage daughter.
The officers grabbed Hersi and pushed him off the train to make an arrest at 5pm on October 11 last year.
Inspector Sharon Turner said: “Our plain clothes teams are specially trained in identifying dangerous sexual offenders like Hersi, who will do their level best to commit such crimes without notice.
“In this case, the victim and her family didn’t even realise what was happening until our officers quickly intervened.”
Hersi, 32, of Limehouse, was found guilty of sexual assault at Inner London Crown Court on 5 May.
The judge sentenced him to 18 months in prison and a ten year Sexual Harm Prevention Order which prevents him from intentionally standing behind or next to any female he doesn’t know in a public place.
He was also ordered to pay a victim surcharge of £187.
Insp Turner added: “Passengers should feel reassured to know we have plain clothes patrols like this taking place across the Underground day and night to keep everyone safe. If you ever have any concerns while travelling please do text us on 61016.”
