An investigation into the matter revealed the fast-food restaurant had nothing to do with writing the obscenity on the officer’s coffee cup, reports KSNT.

In a statement, Police chief Brian Hornaday said the note was “fabricated by a police officer no longer employed with the agency”.

“Now, this is absolutely a black eye on law enforcement,” Hornaday said.

The officer, who was with the department for two months, is understood to have told the police chief the message was meant as a joke.

The officer will remain unidentified as the matter is a “personnel issue”.

When news of the incident broke, officer claimed he had visited a drive-through in Junction City, Kansas, on his way to work on Saturday when he received the insulting note.

A photo showing the coffee cup and offensive missive, which read “F***ing Pig”, was then posted to Facebook by Chief Hornaday where it was then shared more than 4500 times.

“This is what he paid for,” he captioned the post, adding: “This is likely the act of one person and not a representation of the company.”

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When the incident was brought to McDonald’s attention, it’s understood they offered the police officer a free lunch.

However, this was swiftly declined, with the police chief stating a free meal wouldn’t make up for the offence the note had caused.

“No thank you. A Big Mac and large fries doesn’t make up for it,” wrote Chief Hornaday.

“The US Veteran who continues to serve deserves much more.

“This is not only bad for McDonalds but is also a black eye for Junction City.”

The Junction City Police Department said in a Facebook post the incident wasn’t representative of how the majority of residents felt about cops.

“We would like that officer to know this is not representative of how the majority of residents in Junction City feel about Law Enforcement,” the post said.

“JCPD has a very wonderful and supportive community we are honoured to serve. We are hopeful that the business this occurred takes appropriate action.”

In the wake of allegations against McDonald’s in Junction City, owner Dana Cook released statement defending staff.

Cook said a review of security footage from “every angle” inside the restaurant showed message was not scrawled by employees.

“My McDonald’s have the utmost respect for all members of law enforcement and the military and were troubled by the accusation made,” Cook wrote in the statement.

“We look forward to working with Chief Hornaday as he continues his investigation.”