Well, that's not entirely accurate...
He was indicted, and the murder charge was dismissed after he plead guilty to obstruction of justice and got 12 months probation and he reached an agreement to testify against the other 2.
He also settled civilly with the families of the two murdered...
The whole case is a bit... weird. I definitely think he was involved, but not sure to what extent exactly. There's a bit more to the story than the media just being the media though.
Two people were murdered and no one was ever convicted. Lewis was obviously there, and fled with the two he testified against, then admitted to lying to police about the incident the following day. Not sure how you define accessory but I, personally, think that pretty much fits it.