Complex sentence: When reports of the bus burning and beatings reached US Attorney General Robert F. Kennedy, he urged restraint on the part of Freedom Riders and sent an assistant, John Seigenthaler, to Alabama to try to calm the situation.
Split into simpler sentences: When reports of the bus burning and beatings reached US Attorney General Robert Kennedy, he urged restraint on the part of Freedom Riders. He sent an assistant, John Seigenthaler, to Alabama to try to calm the situation.