04/29/1998 AT 12:00 AM EDT
Kenneth Waters, who was imprisoned for 18 years for a murder that his sister Betty Ann Waters was convinced he did not commit, was freed on Thursday -- thanks to his sister, who put herself through law school in order to help him, reports ABC News. In 1983, Betty Ann Waters was a divorced mother of two and a high school dropout when Kenneth was convicted of murder and robbery and sentenced to life for the murder of Massachusetts woman Katharina Brow. Thursday, Betty Ann helped represent her brother as a judge released him on personal recognizance pending a decision on a new trial. "There were samples of blood that were found at the scene of the crime on different materials, towels and things like that," Betty Ann told ABC News after her brother's release. "The blood evidence is what we were looking for." After Kenneth's conviction, Betty Ann earned her GED and enrolled at the Community College of Rhode Island, where she got her associate's degree. She later transferred to Rhode Island College, where she earned a bachelor's and master's degree in education (because she planned to support herself and her family by teaching while she attended law school). Betty Ann enrolled at the law school at Roger Williams University in Rhode Island in 1995 and began investigating her brother's case. Friday morning, sitting with Betty Ann on the "Today" show, Kenneth said, "This proves what your mother tells you: Never hit your sister."