Perhaps JC occasionally visited one of her parents at the JO plant for some time. Don't know, if this was allowed because I don't know, which position their parents had, if they both had a single bureau or if hygiene regulations had to be observed or not. At the plant, IF Jayme was a visitor, different men could have seen her (with pleasure) and would have known, to which parent she belonged.
Another thought, I had: Why does nobody contemplate to the possibility, that both females were the target ie. for sex assault and not only the teenager girl?