China is believed to execute more prisoners annually than all other countries combined, though the exact figures remain a closely guarded state secret.
With an annual salary ranging from $125,133 to $162,672, the astronauts could have earned between $93,850 and $122,004 in basic pay for their nine-month stay in space.
Most of the documents appeared to relate to the 1964 investigation conducted by the Warren Commission, which was led by Supreme Court Chief Justice Earl Warren.
Earlier on Tuesday, investigators from the Loudoun County Sheriff's Office, Konanki's hometown law enforcement, said they do not believe Riibe was involved.
Sudiksha, an Indian national who moved to the U.S. as a child, had been on a Caribbean vacation with five female college friends when she was reported missing on Thursday.