A Brooksville dental assistant who was involved in a 1996 auto accident in which two people were killed pleaded no contest Wednesday to a charge of DUI/manslaughter. In addition, Gail C. Chapman, 44, of 9352 McIntyre Road in Brooksville pleaded no contest to one count of driving under the influence of alcohol/serious bodily injury. According to the Florida Highway Patrol, Brooksville residents David A. Elvidge, 34, and Donna C. Colgan, 81, were killed Jan. 12, 1996, when Chapman was driving south on Jasmine Drive and slammed into the back of a 1988 Toyota in which Elvidge and Colgan were riding, sending the car through a fence at the Brooksville Cemetery and into a tree. Chapman was treated for minor injuries at Brooksville Regional Hospital. Chapman, who declined to comment on the pleas Wednesday, faces a state-mandated minimum of 14.6 years in prison; sentencing has been scheduled for May 8.