Liz Garbus (What Happened, Miss Simone?) is a documentary film maker, and Lost Girls is one of those "based on a true story" movies, which makes it an interesting choice for Garbus' first fiction film. And sure enough, Lost Girls plays a lot like a documentary, except for the obvious fact that there are actors like Amy Ryan (Gone Baby Gone) rather than the actual people. Ryan is perfectly cast ... well, anytime Amy Ryan is on the screen, she is perfectly cast, because she's a great actress ... she can make you forget she's an actress, which is appropriate for this kind of docudrama.
Which isn't to say that Ryan is low-key here. Her anger throughout is palpable, and it drives a movie that we know from the outset will have no closure (we are informed at the beginning that Lost Girls is "an unsolved american mystery"). Her Mari Gilbert is a mess, but when her eldest daughter disappears, Mari persists in searching for the truth, most often by pressing the police, who aren't good for much. If this were a different story, Gilbert might be plucky ... at one point, a detective calls her "feisty", which amounts to the same thing. But Mari is a bit deranged, which is partly why she is so dedicated to finding what happened to her daughter, but which doesn't really match with a stereotypical pluckiness. But, there is no avoiding the conclusion ... in real life, the culprit has never been found ... and whatever resolution Gilbert achieves must remain philosophical at best.
Stay for the brief words at the end which, in good true-crime fashion, tell us what has happened to the characters since the film's conclusion. There, we learn of one person's closure that is unexpected and unsettling, to say the least.
(Here is a letterboxd list of Film Fatales movies.)