2,221, Keeping Women From Becoming Prohibited

Hilchos Issurei Biah 18:27

Pursuant to the previous halacha (about a conquered city), if it was possible for one woman to escape without being seen, or if there was a hiding place in the city, even if it could hold just one woman, it keeps all the women from being prohibited to kohanim.

Hilchos Issurei Biah 18:28

It keeps the women from being prohibited to kohanim as follows: every woman who claims to remain undefiled is taken at her word because she could have claimed to have escaped from the city when it was conquered or that she was in the hiding place. Therefore, she is taken at her word if she says that she didn’t escape or hide but that she was not molested.