AN asylum seeker who came to Australia illegally by boat has been charged for allegedly raping a teenage foster-home girl he held captive for one month. The girl was only rescued when police found her running “barefoot” down a Western Sydney street at 1.30am yesterday. It is alleged Bangladeshi national Rashadul Islam, 29, grabbed the girl and attempted to drag her away before the police intervened.  He met the 15-year-old, it is understood, in a chance encounter after she left a Western Sydney group foster home last month. The Saturday Telegraph has been told she was reported missing by the facility ­almost immediately, but was not seen again until police ­allegedly found her being chased along Balmoral St in Blacktown by Islam. When questioned by police, the teenager alleged Islam had sexually…