LINCOLN, Neb. (AP) – A Lincoln teenager has pleaded guilty as an adult to manslaughter and robbery charges in the beating of a man in a city park. The Lincoln Journal Star says 17-year-old David Centamore entered the plea on Thursday as part of a deal with prosecutors. He was charged with first- and second-degree murder in the death of 49-year-old William Morgan in May.  Authorities say Centamore and two others beat Morgan during a robbery. Police found Morgan in the park and took him a treatment center, where he found unresponsive the next day. He was pronounced dead at a hospital. Centamore faces up to 70 years in prison. Sentencing is Oct. 11. Two other teens also face charges in Morgan’s death.