Which one is correct: "Where she fit in" VS. "Where she fit"?

I read the following sentences in a New York Times article ( "https://www.nytimes.com/2012/12/31/nyregion/erika-menendez-suspect-in-fatal-subway-push-had-troubled-past.html"):

The case of Ms. Menendez, 31, puts renewed attention on a mental health system that is a loose amalgam of hospitals, supported housing, shelters and other advocacy and support groups, in which mentally ill people often bounce from one to the other and ultimately fall through the cracks. It is not known precisely where she fit in.

I wonder if "where she fit in” should be "where she fit" instead. "Where", as I understand, already contains the meaning of 'in the place that' or 'in situations that" so it seems redundant to add in after fit.

What is your opinion? Thanks for your help!

Solution 1:

"Fit in" seems to work better for a specific placement within several alternatives, as enumerated in the example. The "in" gives an impression of fitting into or in between these options (hospitals, housing, shelters, etc).

"Fit" comes across as more binary: she fits or she doesn't.

Having said that I think either usage would be well understood.