If the FBI agent who interrogated Jacob Wetterling’s killer just months after the 11-year-old’s disappearance in 1989 could do it all over again, he would have a casual conversation with Danny Heinrich rather than arrest him and read him his rights, he said Tuesday.

Retired FBI Special Agent Steve Gilkerson said he didn’t know who in the investigation’s command structure ordered the arrest and interrogation of Heinrich in February 1990, but he said investigators lacked the evidence needed as leverage with Heinrich, who was released from custody the next day. He said Heinrich was arrested for allegedly molesting another boy from Cold Spring in January 1989 with the idea of asking him about the Wetterling case.

“It was a Hail Mary effort” to elicit a confession from Heinrich, who was considered a leading suspect in Jacob’s abduction within weeks of his disappearance.

“The only way [the Wetterling] case could have been solved and was solved was by a confession,” Gilkerson said at a news conference he called Tuesday at the Hennepin County Government Center. He said he wanted to refute criticisms by Stearns County Sheriff Don Gudmundson last month that the investigation had gone “off the rails,” in part due to early missteps and blunders by the FBI.

Gilkerson said it might have been a better strategy to interview Heinrich without arresting him. Once that line was crossed, he said, investigators had to read him his rights and Heinrich immediately asked for a lawyer, shutting down the interview. Stearns County prosecutors said they didn’t have enough cause to hold him and he was released from custody the next day.

In reviewing the investigative work two weeks ago, Gudmundson called Heinrich’s arrest “the most fatal flaw” in a 27-year investigation. Jacob’s whereabouts remained a mystery until Heinrich confessed in 2016 to kidnapping and killing him and leading authorities to his remains in a rural area outside Paynesville, Minn., where Heinrich lived at the time of the abduction.

Gudmundson’s critique coincided with the release of tens of thousands of pages of Stearns County investigative documents that had been closed while the case remained active. Gilkerson sat through that presentation — at the Stearns County Law Enforcement Center in St. Cloud — and rebutted the sheriff at that time. But he said Tuesday that he had wanted to say more.

“The main thing I would like to do is tell the sheriff to stop this,” Gilkerson said, referring to Gudmundson’s criticism. “This was starting to heal. He ripped the scab off for no reason.”

Gudmundson, in a written statement responding to Gilkerson’s complaints, said the “multiple missteps” in the investigation “almost appeared to be acts of willful blindness.”

Among the clues that he said should have established Heinrich as the main suspect: a deceptive reading on Heinrich’s polygraph test; Heinrich’s resemblance to the composite sketch of the abductor; tires and shoe marks found at the scene that were “consistent” with those on Heinrich’s car and shoes; similarities between the car used in Jacob’s kidnapping and the earlier abduction in Cold Spring; a fiber found on the Cold Spring victim’s snowmobile suit that was consistent with the interior of Heinrich’s car; clothing and a handgun belonging to Heinrich that were similar to that worn and used by the attacker.

Much of what Gilkerson said Tuesday he had said before, including that Gudmundson, who is filling out the term of former Stearns County Sheriff John Sanner, who retired last year, wasn’t involved in the investigation and had the benefit of hindsight.

He disputed Gudmundson’s claim that tire tracks and footprints at the Wetterling abduction scene matched Heinrich’s. They were similar, but not a match by evidentiary standards, he said.

He also defended the decision to investigate hundreds of tips about other suspects, including known sex offenders, after the uneventful interview of Heinrich.

“We had other suspects that looked every bit as guilty as he did,” Gilkerson said.

A key part of Gudmundson’s critique last month was that the FBI and Stearns County investigators wasted time looking at other suspects when they should have stayed focused on Heinrich. Gilkerson said he moved to a different assignment within a few months of his interview of Heinrich and could not comment on what happened after he departed.

Before Gilkerson spoke Tuesday, a public relations aide handed out copies of his résumé, which indicated that he was a veteran investigator at the time of Wetterling’s abduction, signing on with the FBI in 1968 and spending 11 years in New York City.

Gudmundson last month also faulted a lack of cooperation among local, state and federal agencies, and seemed to place most of the blame on the FBI, which led the investigation under agent Al Garber. Garber didn’t attend Gilkerson’s news conference Tuesday, but stood up and disputed Gudmundson at length in St. Cloud last month.

Jacob was abducted by a masked man at gunpoint the night of Oct. 22, 1989, as he, his brother and best friend headed home from a convenience store in St. Joseph, Minn., where they’d gone to rent a video. His whereabouts remained a mystery until Heinrich, who had been jailed for a year on child pornography charges, told authorities in late summer 2016 that he killed the boy the night he kidnapped him, then buried him outside Paynesville.