漏网 is a verb-object phrase (v.o.) that literally means 'to leak through the net', used figuratively for criminals or wrongdoers escaping punishment or justice. Common in the idiom 漏网之鱼 ('a fish that slipped the net'). As a v.o., it is normally used as a whole unit — you can insert an aspect marker like 了 (漏了网) to show completion, but the object 网 is almost never modified by a measure word or separated further. You cannot attach an object after 漏网; instead use a passive or topic structure like '让罪犯漏网' ('let the criminal slip away').