hmmm it would seem feasible that VAL kept the journals somewhere, just for sentimentality Maybe she digitalised them and put them in her own memory bank, thinking that it's 'unshakeable' (although as evidenced by X0N's tinkering, not completely safe). I think people would know but VAL would have told the higher-ups an edited story, leaving out info about how close the two used to be, the research that 4KT did and also her conclusions. She's essentially using 4KT's death to scare the NOTECs into following her regime even closer, and she probably made sure that any crew members present were dead or imprisoned