HOUSTON, Texas (WPVI) -- It's a growing mystery outside of Houston.A barefoot woman was seen on surveillance video ringing a doorbell in the middle of the night, and then vanishing.The woman appears to look in distress, she doesn't have shoes and some think it looks like she has restraints around her wrist.The video was captured on a doorbell camera around 3:30 a.m. Friday.People who live nearby are concerned.Police say they have no idea who she is.But they are reminding people not to open their doors, instead, they want you to call 911.------