A man sexually assaulted a woman on a rooftop near Clinton Street in the Lower East Side on August 3, the police said. The pair entered the building together at 2:50 a.m. and then the suspect, who is said to be 5-foot-5 and in his early 20s, assaulted the victim and fled. Just yesterday, the Manhattan District Attorney announced the conviction of a 39-year-old man who was linked to a sexual assault in the East Village in 2008 thanks to a state DNA database.