CHICAGO: A private investigator pleaded guilty Monday (Dec 11) in US federal court of trying to illegally obtain President Donald Trump's tax information last year during the height of the contentious election campaign.

Jordan Hamlett, 32, of the state of Louisiana admitted to a charge of false representation of a social security number - the common identifier Americans use for everything from credit card applications to filing taxes.

Hamlett, who faces up to five years in prison, used Trump's social security number to begin a federal student loan application online - an unsuccessful attempt to trick the system into pulling Trump's tax information from Internal Revenue Service records, prosecutors said.

Hamlett's lawyers have previously argued that their client was simply a hacker trying to discover vulnerabilities in federal systems.

"The federal government has been unable to produce one shred of evidence that Hamlett was intending to do anything other than his stated intent - to discover, out of sheer curiosity, whether Trump's tax information could be accessed," his attorneys said in an October court filing.

Billionaire Trump has refused to release his complete tax records, reversing the standard held by all presidential candidates and office holders since Jimmy Carter in the late 1970s.