They made it abundantly clear during the Dark Years.
Thousands of unaccompanied kids were sent to live with "sponsors" who were lightly-vetted. This practice was brought up many times in congressional hearings with the execrable Alejandro Mayorkas and his flunkies. The practice continued under the Biden Administration.
Unfortunately, it will be left to right wing sources to chronicle the voluminous incompetence and mendaciousness of the Biden Administration. Imagine trying to recount the lying and abject failures of the Biden Administration's border policies in a single book or monograph? Imagine even trying to confine the Afghanistan troop removal disaster to 500 pages.
Link: https://www.dailywire.com/news/teen-molested-by-illegal-alien-who-biden-admin-sent-her-to-live-with-police-say