In it, he said: "Please inform your FBI director here in NZ that his life is in danger and he will not leave this country alive.
"Must suck because you know that police can't do anything to me here," he wrote.
He also said: "There is a bomb at your Embassy" and "Another bomb will go off soon evacuate the Embassy and f*** off or die."
McLean also posted numerous Facebook message to the United States Embassy's Facebook page and posted a message to the New Zealand Police Facebook page.
He also sent "extremely concerning" emails to the Government Communications Security Bureau, National Cyber Security Centre, Inspector General of Intelligence and Security and MP Chris Finlayson.
Read more:
• Rotorua man who threatened FBI director: 'I've learned a valuable lesson'
Judge Kim Saunders told McLean freedom of speech was an important right that must be protected, but he could not behave in this way especially given recent events in the United Kingdom.
She said McLean went on a social media "rant" and expressed extremely strong views about the US being the No 1 terrorist nation.
She said his "appalling comments" clearly crossed the boundaries and his posts online were considered real threats.
She said given the terror attacks in the UK in recent weeks, comments like this could not be viewed in isolation anymore.
"I am not for one minute suggesting you are responsible for that but there is a big picture here."
Judge Saunders acknowledged a request from McLean's lawyer, Erin Reilly, that he be sentenced to community work given his remorse.
She said she imposed a community-based sentence in the hope it would help rehabilitate him.
The judge ordered McLean be subject to supervision for 12 months and undertake drug and alcohol counselling, and any other counselling his probation officer directs. McLean was also sentenced to 140 hours of community work on the charge of making a false statement.
He had his current court fines of $4844 wiped and replaced with a further 40 hours' community work, which was to be served accumulatively.
McLean had previously told the Rotorua Daily Post he openly supported Palestine and Russia.
He had said headlines in the media about the US Government had tipped him over the edge and what he said was "stupid" and out of "pure frustration".
