A state judge said he doesn’t believe the testimony of the first of two teenagers to stand trial in connection with the fatal beating of a taxicab driver last year in Waipahu.

He therefore found Robles guilty Thursday of manslaughter.

Circuit Judge Dexter Del Rosario scheduled sentencing for September.

The possible penalties for manslaughter are either a 20-year prison term or 10 years’ probation. However, defense lawyer William Jameson said he will ask Del Rosario to sentence Robles under state law intended for adult defendants under 22 years old, which would reduce the prison term to eight years. Robles is 19.

The other teenager, 18-year-old Kilani Derego, is scheduled to stand trial in October. Robles will be required to testify.

Robles said he and Derego, his childhood friend from the Big Island and fellow resident of a Hale Kipa group home in Manoa, entered a cab driven by Charlys Ty Tang in Waikiki just past midnight May 1 last year and went to Waipahu. But when police arrested him six days later, he said he wasn’t in Waipahu.

“The court finds that the various accounts by Mr. Robles in court and during police interrogation were either admittedly false, inconsistent, contradicted or uncorroborated,” Del Rosario said. “Parts were implausible or otherwise incredible in light of the evidence presented.”

When they arrived in the Waipahu Times Supermarket parking lot, Robles said Derego and Tang got into an argument and Derego started beating Tang. He said he kicked Tang, who was on the ground holding on to Derego’s leg, to break his friend free, then tried to pull Derego off Tang. 

An ambulance transported Tang in critical condition to the Queen’s Medical Center, where he died later that day, his 41st birthday.