The email sent by the officer, based in Kronoberg county in southern Sweden, was considered so threatening, that it caught the attention of Swedish security service Säpo as well as the Swedish military intelligence agency MUST.
In the email, the man muses over “how you politicians can abuse an entire people” with such “extreme fees for heat and electricity”.
He goes on to complain about profits earned by privately managed energy firms and politicians' inability to address the issue, viewing their inaction as a sign of “incompetence”.
“When the wolf hunt is over, maybe it's time to deal with the politicians,” the 47-year-old writes in closing.
After being let go, the officer contested the decision, claiming the email wasn't meant as a threat to the prime minister.
Rather, the message was simply meant as a protest against energy company profits and the government's complacency on the matter.
“I sent this mail to them because I was personally bloody irritated at the government,” the officer wrote in an email to the commanding officer of the naval base where he was stationed after he was fired.
However, the 47-year-old also sent emails to colleagues which they considered threatening, according to the Armed Forces human resources committee ruling.
The committee added that it was "not appropriate" to reassign the officer to any other position within the Armed Forces.