As Jim Cunningham isn't caught in the Primary Universe, doesn't that mean Donnie failed in revealing him as a criminal?
The Philosophy of Time Travel, the chapter Dreams states…
When the Manipulated awaken from their Journey into the Tangent Universe, they are often haunted by the experience in their dreams…. Those who do remember the journey are often overcome with profound remorse for the regretful actions buried within their dreams…"
This is seen in the film during the Mad World sequence when Jim Cunningham wakes up sobbing with what appears to be guilt.
To further prove this, hidden on DonnieDarkoFilm.com was a newspaper article about Jim Cunningham’s suicide, which occurs in the Primary Universe on October 12, 1988, just days after Donnie’s death.
Jim Cunningham was found dead on the fourteenth hole of the Country Club golf course on October12, 1988. He had apparently shot himself. Before he committed suicide he cleared out his entire mansion including his child porn dungeon. The police found his suicide note but nothing else… his dirty secret was never revealed. He actually shot himself on the same hole that Donnie wakes up on after his initial conversation with Frank. this was also the first point Donnie meets him.
Also, Donnie did not fail in revealing him as a criminal because that was never his main goal. Frank told Donnie to burn down Cunningham’s house, which eventually led to the discovery of his kiddie porn dungeon.
This leads Mrs. Farmer to go to Cunningham’s defence instead of on the trip with Sparkle Motion, causing Rose Darko to go on the trip instead, which allows Donnie and Elizabeth to throw a party.
Frank leaves this party to get more beer and has to drive by Grandma Death’s house on the way back, which is where Frank runs over Gretchen and Donnie kills Frank.
Without this party, Gretchen wouldn’t have been killed. So, according to the Philosophy of Time Travel, since the Ensurance Trap (Gretchen’s death, caused by Frank) was successful, the Living Receiver (Donnie) is left with no choice but to use his Fourth Dimensional Power to send the Artifact back in time into the Primary Universe before the Black Hole collapses upon itself.
So burning down Cunningham’s house was much more important than Donnie revealing him as a criminal (although Cunningham’s suicide shows that he still suffers for his actions).
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