OKLAHOMA CITY — A Salt Lake City attorney is arguing in a lawsuit that the FBI has video of the Oklahoma City bombing that shows a second person was involved. The case is at the heart of Jesse Trentadue’s quest to explain his brother’s mysterious jail cell death 19 years ago, which has rekindled long-dormant questions about whether others were involved in the deadly 1995 blast. What some consider a far-flung conspiracy theory is at the forefront of his Freedom of Information Act lawsuit against the …