A woman posing as a health care worker at a Billings hospital accompanied doctors on multiple patient checks, leading Montana health officials to warn employees at other facilities to be on the lookout for an impostor wearing scrubs or a lab coat. The woman has breached security at Billings Clinic an undetermined number of times, prompting Billings' other hospital, St. Vincent Healthcare, to circulate surveillance photos and a warning memo to employees. "She is a talented liar and will invent all sorts of stories as to who she is and what she is doing," Curtis Harper, St. Vincent's regional director of Public Safety, Emergency Management and Forensic Investigation, said in the memo.