Police supporters and police protesters faced off Sunday in downtown Denver, waving American flags and photos of local citizens shot by officers in each other’s faces.

The event began when Denver businessman Ron MacLachlan decided to hold a pro-police march to show his two teenagers a positive portrayal of law enforcement after watching riots in Baltimore after a man died in police custody.

The march became a rally Sunday that turned into a clash of cultures and drew about 250 people.

MacLachlan watched as protesters filled up his group’s gathering space in Civic Center.

“This is a prime example of why this event needs to be done,” he said.

Police supporters like The Blue Knights of Colorado, Colorado Concerns of Police Survivors, active law enforcement officers and area residents turned out to show their support for police and listen to a lineup of pro-police speakers.

But people carrying massive signs displaying the names of loved ones killed by police and megaphones also came out in droves.

The protest chants were so loud that it forced the police supporters into a rotunda so their speakers could be heard.

State Rep. Lori Saine of House District 63 found out about Mac Lachlan’s rally and wanted to voice her support for police.

“I’m here today because there seems to be increasing condemnation for those who protect us,” Saine said.

Todd Nading held a photo of his father, Merele Nading, a police officer who was killed in the line of duty in 1971.

Nading said he was disturbed by the scene unfolding in front of him.

“The reason this country is as good as what it is, is because of our police force and military,” Nading said. “It’s upsetting to see so many uneducated people who don’t understand how bad a country can get.”

Barbara Fallon inched up to a group of young protesters who were shouting profanity about police.

Holding an American flag, two red balloons and her cane, she stood her ground among the chanting opposition.

“I’m feeling that we have let thugs take over this event,” Fallon said. “The criminals are becoming the stars, and the law enforcement are becoming the criminals.”

MacLachlan said he did not expect so much opposition.

“Everybody has a right to protest, but we filed a permit and this is our time to be heard,” he said.

Daniel Gallegos stood outside the rotunda holding a sign with Paul Castaway’s photo on it.

Castaway was shot and killed last week by Denver police, and his family disputes the police’s version of events leading to Castaway’s death.

“They killed my brother-in-law,” Gallegos said. “I’m here so they don’t keep killing people.”

MacLachlan said a bridge needs to be built between the public and the police.

“All I’m hearing is F the police and profanity,” Mac Lachlan said. “Are those concerns I think are warranted? Absolutely not.”

Michael Hesse is a cofounder of the Denver Police Museum. He said he recognizes that there have been some “bad apples” in law enforcement but that a pro-police rally was not the place to voice those concerns.

“Shouting over us is anti-American,” Hesse said. “I feel like my rights today were violated.”

Elizabeth Hernandez: 303-954-1223, ehernandez@ denverpost.com or twitter.com/ehernandez