Mahipal Singh was absconding since they assaulted the 16-year-old girl in Najafgarh area in southwest Delhi on August 11.
He was arrested in R K Puram area on the basis of a tip-off, police said. Singh was also wanted for assaulting the driver and conductor of a Delhi Transport Corporation bus in June.
Six of the accused Narender, Vikas, Rajbir, Narender, Shekhar and Sandip Ahuja had been arrested from the scene of crime itself while one of them, Jai Prakash, was apprehended the next day.
The girl had been lured by the driver of the private bus Narender, with whom she was on friendly terms, to the vehicle at around midnight where he and his friends assaulted her.
