ST. PAUL, Minn. -- A political attack mailer aimed at mayoral candidate Melvin Carter III drew widespread condemnation Friday, and led to calls for new leadership in St. Paul's police officers' union.

The postcard, sent by Building a Better St. Paul, an independent political expenditure group, decried rising violent crime in the city and declared, "As gun violence rages across St. Paul, Melvin Carter has shown zero interest in public safety."

It follows with a quote from Officer Dave Titus, the president of the St. Paul Police Federation, "We need a mayor that will make public safety a priority."

That was standard campaign fare, but the mailer then became personal with a banner that read, "Over 100 shots have been fire since August 15 when Melvin Carter's guns went missing" -- a reference to a newspaper story that two guns had been stolen in a burglary of Carter's home.

"When you see something like this that is perceived very, very clearly in the African American community as a racist attack on an African American candidate for mayor, then it undercuts years of efforts," St. Paul Mayor Chris Coleman told KARE.

"To suggest that the victim of a crime is somehow responsible for an increase in gun violence is just ludicrous!"

Melvin Carter III is the only African American candidate in the mayoral race. His father Melvin Carter Jr. was a police officer in St. Paul for 30 years.

Coleman called for the entire board of the St. Paul Police Federation, including Officer Titus, to step down from their leadership roles in the union.

"When the federation leadership is undercutting the leadership of the department, undercutting the men and women of the department it’s time for them to go."

One of Coleman's competitors in the 2018 governor's race, Congressman Tim Walz, also condemned the mailer. The Walz campaign sent the media a photo of the lit piece.

Building a Better St. Paul, in a statement filed with Ramsey County Campaign Finance, showed most of its contributions came from the St. Paul Police Federation and St. Paul Area Chamber of Commerce. Most of the organization's expenditures were listed as, "in support of Pat Harris campaign."

Former City Council Member Pat Harris is Carter's top opponent in the race, and has been endorsed by the police federation. Harris also condemned the mailer.

"I categorically reject it. I had nothing to do with it," Harris told KARE, saying he had called Carter to reassure him that his campaign had no control over what Building a Better St. Paul was doing.

"I've vowed to stay positive, and then negative campaigning from an outside group comes into this thing and clouds it with preposterous theories, when what I’m trying to do is be positive about our message."

Carter himself tried to remain above the fray on Friday, but agreed the Mayor Coleman's assessment it's time for leadership to change in the union.

"What happened this week was disappointing and alarming. It wasn't shocking."

Earlier in the week Titus drew fire for an open letter to Carter from the union's political wing, The Saint Paul Police Federation Political Awareness Committee, asking Carter why his guns weren't locked away and why he didn't know the serial numbers of the weapons.

Titus responded to uproar over the letter with a statement apologizing for the letter, but defending gun violence as a legitimate campaign issue.

Titus declined interview requests on Friday but issued a statement saying the Building a Better St. Paul mailer had already been sent before he apologized for the letter.

"The letter released by the Federation on Tuesday was an ill-advised political attack meant to highlight inconsistencies, that was in no way shape or form racially motivated," Titus said in a statement distributed by a media relations firm.

"Once the ramifications of the letter became clear I issued a sincere apology to the Carter Family, an apology I reiterate today. In no way were we implying these guns were used in the commission of a crime, rather that we need a Mayor whose priority is public safety."

He said that the union's political wing and Building a Better St. Paul would cease activities for the remainder of the 2017 election cycle which will end Nov. 7 on Election Day.

Titus said it was up to union members to decide whether he should longer be their leader. He said that he alone was responsible for the communications, and that the remainder of the Police Federation board shouldn't be blamed.

"The current president of the federation is saying he was the only person who even knew about this," Mayor Coleman remarked. "I cannot believe that, and if that is the case then the board has abdicated its responsibility."

Coleman hasn't endorsed anyone in the race, and said he has respect for all of the leading candidates.