CRANSTON, R.I. — It was a warm spring day and dozens had gathered at the city’s police headquarters for a memorial service honoring officers killed on the job.

The crowd fell silent as a man read the names of 47 Rhode Island police officers killed. Their names and titles echoed through the parking lot.

But North Providence Acting Police Chief Christopher Pelagio’s mind was elsewhere. He began to make “strange faces” and mouth expletives to a Cranston sergeant who was presenting the American flag, according to an internal affairs investigation about an “altercation” between Pelagio and the Cranston officer.

Pelagio is not named in the report, but Col. Michael Winquist, the chief of the Cranston police, confirmed the “incident” involving the acting chief was being investigated.

The report was released days after Mayor Charles Lombardi suspended the acting chief, in that position since 2014, with pay “until further notice.”

Pelagio was not invited to the service. He did not let officers know he was coming. He had never attended the annual memorial before, the report states.

But a decades-old beef with the Cranston sergeant who is married to Pelagio’s ex-girlfriend may have drawn him to the event, the sergeant said in interviews with police. Pelagio and the sergeant — who was not named in the report — have an “extensive and acrimonious history ... [that] began well over twenty years ago.”

The sergeant said that when he began dating his now wife in the 1990s, she had “recently been in a relationship” with Pelagio. His first interaction with Pelagio was at the Boston Billiards pool hall in Warwick around that time. Pelagio tried to fight him, which surprised the boyfriend, who said he had no idea who Pelagio was.

Shortly after, the man was hired by Cranston police. Pelagio then “approached and contacted members of the Cranston police in an attempt to prevent [the sergeant] from obtaining a job as a police officer,” according to the report.

More than 20 years later, on May 18, Pelagio drove to the memorial service with Deputy Chief Charles Davey. And as the honor guard walked into the ceremony, Pelagio said, “Uhhh, there’s that guy,” Davey said in an interview with Cranston police.

Throughout the ceremony Pelagio locked eyes with the sergeant, according to multiple witnesses who were interviewed.

“‘He said, "We’re gonna have a problem here with this guy,’” Davey told Cranston police. “‘The [chief] said, ‘Yeah, yeah, yeah, I’ll talk to him. I’ll talk to him....look he’s eyeballing me. He’s been eyeballing me the whole time.’”

As Pelagio and Davey walked toward their car to leave they approached a group of officers chatting in the parking lot. This was intentional, Davey said. They did not want to look “like we were avoiding,” he said.

Pelagio, with his phone cupped in his hand, walked up to the Cranston sergeant, getting inches from his face. Davey said he believed Pelagio’s phone was out so he could “collect evidence.”

The sergeant, who was interviewed as part of the investigation, said Pelagio said hello in a “shrieking voice.”

“His lip was twitching and his body seemed to be almost shaking,” the sergeant says in an interview transcribed in the report.

According to the sergeant, Pelagio said: “‘You’re nothing but a two-bit [expletive] punk.”

“With his two hands he began beckoning me and asking me what gym I went to,” the sergeant said in the report. “[Saying] that he’d fight me anywhere or box me...at this point his behavior was so erratic, so embarrassing, so disgusting that it was actually comical.”

Another Cranston officer separated the men, but Pelagio said he wanted the sergeant to be “charged criminally with assault due to chest-bumping him.” But security footage shows no “chest-bump” happened. Cranston police called Pelagio in May and told him what they saw on the footage. He said he “wanted something done...and also advised if we did not handle it, he would go the Rhode Island State Police (to file a complaint).”

Pelagio then stopped answering phone calls, emails, and letters from the Cranston police about the investigation. He was never interviewed, Winquist said.

Pelagio makes $105,000 annually and gets overtime because he is a member of the union. Because of his union status, he is protected by the Law Enforcement Officers Bill of Rights. This means the town must hold a hearing where other police officers determine whether his behavior violates the code of conduct.