Sirhan Sirhan, the man who assassinated Robert F. Kennedy, is eager to see the government's classified files on RFK's assassination ... he's searching for an answer to a question he's always wondered -- was anyone else involved???

Sirhan's attorney, Angela Berry, tells TMZ ... they hope the FBI files President Trump just ordered to be released will finally paint a full picture of what happened that fateful day in 1968 when RFK was shot dead while running for president.

Angela tells us Sirhan's legal team has gotten some FBI files over the years, but they were redacted ... and they're hoping Trump's action opens the floodgates for the whole truth to come out.

RFK's son, Robert F. Kennedy Jr., revealed in 2018 he doesn't believe Sirhan fired the shots that killed his dad ... and Sirhan claims he doesn't remember shooting RFK.

Sirhan's attorney says his short-term memory was impacted by the trauma of growing up in war-torn Palestine, and they want to pore over the files to see if anyone else was involved in RFK's assassination ... especially given speculation the CIA was involved.

RFK was assassinated at the Ambassador Hotel in L.A. the night he won the California Presidential Primary. Sirhan shot Kennedy in a kitchen pantry, moments after RFK declared victory ... or that's at least been the official narrative. Sirhan's still in prison for the crime.

It will be interesting to see what's in the government's RFK files ... and if Sirhan's suspicions are confirmed.

Stay tuned ...