ST. CLOUD — A man questioned several times in the slaying of a Cold Spring police officer fled from investigators and committed suicide this week, authorities said Friday.

Eric Joseph Thomes, 31, of rural Cold Spring, was a “person of interest” in the killing of Officer Tom Decker, but authorities stopped short of calling him a suspect. Bureau of Criminal Apprehension Superintendent Wade Setter said the investigation into Decker’s death is active and ongoing.

Decker was shot and killed behind a downtown bar in Cold Spring, a central Minnesota town of about 4,000 people about 75 miles northwest of Minneapolis. He was responding to a report of a possibly suicidal man when he was shot.

A suspect — the man Decker had gone to check on — was quickly arrested, but released days later without charges. The investigation appeared to founder after that. A police document said Decker’s partner had initially backed away from the scene, losing sight of the apparent shooter. An intense search failed to find a .20-gauge shotgun believed used in the slaying.

Setter said investigators had interviewed Thomes several times about Decker’s slaying based on a tip that came in after a reward of up to $100,000 was offered in the case. He said they had found “inconsistencies” in Thomes’ responses and were seeking to interview him again shortly after 2 p.m. Wednesday, but when they arrived at his home, he fled to a metal outbuilding.

Thomes refused to come out as agents attempted to make contact with him over the next four to five hours, Setter said. When agents entered the building, Thomes had hanged himself, Setter said.

He said investigators found the shotgun used to kill Decker on property to which Thomes had access. He asked for the public’s help in reconstructing Thomes’ “activities and conduct” over the last few weeks. Authorities also said a black van connected to Thomes that had been seen on the night of Decker’s death was recovered.

Stearns County Sheriff John Sanner called the developments significant, but said the investigation is far from over.

“This is a complex case,” Setter said. “We have not excluded anyone as a suspect in this case.”

Authorities did not release a possible motive for Decker’s killing.

“We are trying to figure out what his role is,” Setter said of Thomes.

When asked if there was a suicide note, Setter said he couldn’t discuss it because the investigation is active.

Decker, 31, grew up in the community and was a six-year veteran of the force. He was a father of four children. An estimated 3,200 people, many of them fellow law enforcement officers, attended his funeral service.

Decker’s parents declined to comment on Thomes’ death.

Thomes was convicted of driving while intoxicated in Stearns County in 2011 and had a few other speeding and traffic violations. The St. Cloud Times reported that Decker was one of two officers who had stopped Thomes for possible drunken driving in the past.