exclusive
Barron Hilton has logged on to zipit.com ... refusing to get back to police officers investigating the beatdown he caught at the hands of Lindsay Lohan's pal -- and it's preventing them from making an arrest ... TMZ has learned.
As TMZ first reported ... Miami Beach PD are looking to arrest the puncher -- LiLo's friend Ray LeMoine -- however ... law enforcement sources now tell us they haven't heard back from Paris Hilton's little bro.
We're told police need to speak with him to button up the investigation -- but Barron has fallen off the radar since initially speaking to cops on Friday morning, right after the attack.
As we told you ... multiple sources confirm there was a ton of drugs, including cocaine, inside the party.
Stay tuned ...
