A 28 year old New Bedford woman was robbed last night in her own home.  She told police that someone knocked on her Acushnet Ave apartment door at about 8:30pm.  She asked who it was, but there was no answer.  She opened the door after she heard a second knock.  She says a black man in his 30's with a knife chased her inside and yelled at her to sit down.  He grabbed her purse from the kitchen table and ran away.  The woman was not hurt.  She says that the man had a mole on his face near his nose.  Anyone with information is asked to contact Det. Raul Espinal at 508-991-6300 ext. 139