The fire department that marched under a Trump 2020 re-election flag in full uniform last weekend is facing a possible investigation by the IRS.

A complaint was filed Friday against the Franklin Fire Department, a tax-exempt organization that is barred under federal law from political activity.

It alleges that the fire department “officially endorsed a presidential campaign” by marching under a "Trump 2020 Keep America Great” flag during the Sussex County Firemen’s Association Inspection Day and Parade on Oct. 5.

The Franklin Fire Department was listed as a tax-exempt, section 501(c)(3) organization in 2017, according to the most recent records available online, and under that designation is not permitted to support or oppose candidates for elective public office.

In response to the complaint, an attorney for the all-volunteer Franklin Fire Department said that members did nothing wrong and that the complaint is politically motivated.

“This complaint is political,” said the attorney, George Daggett.

“Clearly the complaint is generated, not by a desire for the truth, but because the Trump flag was carried in the parade,” Daggett said.

A copy of the complaint, with the accuser’s name redacted, was provided Friday to NJ Advance Media. The IRS is empowered to revoke tax exemptions and has a section on its website for anyone seeking to file a complaint, via a 13909 form, against a tax-exempt organization.

The complaint asserts that the fire department "marched flying a partisan political campaign flag in an attempt to influence America’s 2020 national election.”

“The Franklin Fire Department caused Franklin’s residents to question whether, if a resident openly supports a candidate running against Donald Trump or displays a campaign sign supporting a candidate opposing Donald Trump, will the Franklin Fire Department provide the same level of firefighting services as someone who openly supports Donald Trump for president or displays a ‘Trump 2020’ banner or sign,” the complaint reads.

Eight flags are raised outside the Franklin (Borough) Fire Department, but a Trump reelection flag is not included in the display, Oct. 10, 2019Rob Jennings / NJ Advance Media for NJ.com

It also lists a second alleged violation involving gambling that prompted a search, last winter, by the state’s Alcoholic Beverage Control division, along with a reported theft at a spaghetti dinner fundraiser.

Referencing that part of the complaint, Daggett said, “The prior events were never determined to be anything but a mistake.”

A spokesperson for the IRS declined comment, citing federal privacy and non-disclosure law.

The complaint names the fire department’s chief, Fred Babcock Jr., as well as the fire department as a whole.

Franklin Mayor Nicholas Giordano has defended the Trump flag display, while his immediate predecessor, Paul Crowley, has said it was inappropriate.

Both are Republicans and say they support Trump.

Franklin’s top municipal official, business administrator Alison McHose, praised the Trump flag display on Facebook last weekend.

McHose is a former Republican member of the New Jersey Assembly.

Rob Jennings may be reached at rjennings@njadvancemedia.com. Follow him on Twitter @RobJenningsNJ. Find NJ.com on Facebook.