MEMPHIS, Tenn. -- A Silver Alert has been issued for a mentally challenged West Memphis woman who walked away from her parents' house Monday. Sara Lynn Castro, 34, left her home in the 500 block of Belvedere Drive around 11:30 a.m. She was wearing a violet pant set and a black jacket and was possibly carrying a black purse. Search for missing woman (West Memphis Police Department) Capri Reyes said her sister Sara suffered a traumatic brain injury in an ATV accident years ago, and she also walks with a noticeable limp. Reyes said her parents have guardianship over her sister, and they are all concerned about her well-being. AR woman killed in wreck on U.S. 61 in MS "She does go on walks often but has always come home," Reyes said. "Sara will not know a dangerous situation and is very vulnerable. Our nerves are through the roof, as you can imagine." Reyes said Sara does have a phone on her, but detectives said since it’s turned off, they cannot ping the location. Sara Lynn Castro. Courtesy: Capri ReyesSara Lynn Castro. Courtesy: Capri ReyesSara Lynn Castro. Courtesy: Capri ReyesSara Lynn Castro (West Memphis Police Department) Friends and family have turned to social media to find Sara. Several people in West Memphis commented on Facebook they may have spotted her over the last few days, but Reyes said nothing has been confirmed. She said the last promising sighting was at the Flying J Travel Center in West Memphis around 10:30 p.m. Monday. "The employees there confirmed to have seen her. The detective is working on getting that video evidence, but we have not heard anything," Reyes said. If you have seen Sara or know where she is, contact West Memphis Police at (870)735-1210.