Complex sentence: He was once approached by the FBI who wanted him to write an article about Martin Luther King Jr alleged infidelities they had covered under wiretap and told them We're not a peephole journal.
Split into simpler sentences: He was once approached by the FBI, who wanted him to write an article about Martin Luther King Jr's alleged infidelities which they had uncovered through wiretaps. Patterson told them We're not a peephole journal.