He was a US Navy Petty Officer....and enlisted man. He wasn't supposed to be hanging out at brothels so he didn't report it at the time for fear of being punished.
This is from a post about a week or so ago:
The parents were interviewed on msnbc last night & said the navy chief didn't report it right away:
1) because the brothel was off limits
2) because he didn't know anything about the girl being missing until he saw her story in a magazine after he got out of service....he did contact authorities at that time.