In 1973 a school superintendent was killed by the SLA, and a deputy also wounded. In Jan. 1974, two SLA members were charged with murder.
The FBI found documents from the SLA previous to the kidnapping of Patty Hearst. Yes, the Hearst family has wealth and influence and the SLA intended to "use" Patty Hearst as a tool, but I don't believe the reason why the FBI was involved in the Patty Hearst kidnapping/Tania of the SLA case is because her family had wealth and influence. The FBI was involved because the SLA was a revolutionary group that committed murder the previous year, as well as kidnapping Patty, and other activities, in my opinion.
The SLA needed to get the world's attention, hence kidnapping Patty, and their intentions were to use her as a hostage so that the two SLA members who were charged with murder, could go free.
IMOO.