Kilani Derego said he was "fooling around," having sex with his girlfriend in the living room of an apartment on Schofield Barracks where they went to attend a party about the same time taxicab driver Charlys Ty Tang was getting beaten in a Times Super Market parking lot in Waipahu.

Derego, 19, took the witness stand in his own defense Thursday. He is on trial in state court for second-degree murder in connection with the fatal beating of Tang on May 1, 2010, Tang’s 41st birthday.

His testimony matched those of his now ex-girlfriend, the ex-girlfriend’s hanai sister and the hanai sister’s fiancee, who each took the witness stand in Derego’s trial earlier this week.

However, their testimonies contradict what Derego’s codefendant and childhood friend Michael Robles told Honolulu Police Department detectives after he was arrested on May 7, 2010 and what he said during his own trial last year.

Robles told police and testified in his own trial that he and Derego got into Tang’s taxi in Waikiki and when they arrived in Waipahu, planned to skip out on paying the fare. But while he was able to run away, Derego got into an argument with Tang and started beating the driver. Robles said he grabbed Derego to stop him from beating Tang and kicked Tang twice to get him to release his grip on Derego’s legs.