WASHINGTON — A Republican donor and operative from Chicago’s North Shore who said he had tried to obtain Hillary Clinton’s missing e-mails from Russian hackers killed himself in a Minnesota hotel room days after talking to the Wall Street Journal about his efforts, public records show.

In a room at a Rochester hotel used almost exclusively by Mayo Clinic patients and relatives, Peter W. Smith, 81, left a carefully prepared file of documents, which includes a statement police called a suicide note in which he said he was in ill health and a life insurance policy was expiring.

Days earlier, the financier from suburban Lake Forest gave an interview to the Journal about his quest, and it published stories about his efforts beginning in late June. The Journal also reported it had seen e-mails written by Smith showing his team considered retired Lt. Gen. Michael Flynn, then a top adviser to Republican Donald Trump’s campaign, as an ally. Flynn briefly was President Trump’s national security adviser and resigned after it was determined he had failed to disclose contacts with Russia.

At the time, the newspaper reported Smith’s May 14 death came about 10 days after he granted the interview. Mystery shrouded how and where he had died, but the lead reporter on the stories said on a podcast he had no reason to believe the death was the result of foul play and that Smith likely had died of natural causes.

However, the Chicago Tribune obtained a Minnesota state death record filed in Olmsted County that says Smith committed suicide in a hotel near the Mayo Clinic at 1:17 p.m. on Sunday, May 14. He was found with a bag over his head with a source of helium attached. A medical examiner’s report gives the same account, without specifying the time, and a report from Rochester police further details his suicide.

In the note recovered by police, Smith apologized to authorities and said that “NO FOUL PLAY WHATSOEVER” was involved in his death. He wrote that he was taking his own life because of a “RECENT BAD TURN IN HEALTH SINCE JANUARY, 2017” and timing related “TO LIFE INSURANCE OF $5 MILLION EXPIRING.”

One of Smith’s former employees told the Tribune he thought the elderly man had gone to the famed clinic to be treated for a heart condition. Mayo spokeswoman Ginger Plumbo said Thursday she could not confirm Smith had been a patient, citing medical privacy laws.

The Journal stories said it was on Labor Day weekend in 2016 that Smith had assembled a team to acquire e-mails the team theorized might have been stolen from the private server Clinton had used while secretary of State. Smith’s focus was the more than 30,000 e-mails Clinton said she deleted because they related to personal matters. A huge cache of other Clinton e-mails were made public.

Smith told the Journal he believed the missing e-mails might have had been obtained by Russian hackers. He also said he thought the correspondence related to Clinton’s official duties. He told the Journal he worked independently and was not part of the Trump campaign. He also told the Journal he and his team found five groups of hackers — two of them Russian groups — who claimed to have Clinton’s missing e-mails.

Smith had a history doing opposition research, the formal term for unflattering information that political operatives dig up about rival candidates.

For years, Democratic President Bill Clinton was Smith’s target. The wealthy businessman had a hand in exposing the “Troopergate” allegations about Bill Clinton’s sex life. And he discussed financing a probe of a 1969 trip Bill Clinton had taken while in college to the Soviet Union, according to Salon magazine.

Investigations into any possible links between the Russian government and people associated with Trump’s presidential campaign now are underway in Congress and by former FBI chief Robert Mueller. He is acting as a special counsel for the Department of Justice. Mueller spokesman Peter Carr declined to comment on the Journal’s stories on Smith or his death. Washington attorney Robert Kelner, who represents Flynn, had no comment on Thursday.

Smith’s death occurred at the Aspen Suites in Rochester, records show. They list the cause of death as “asphyxiation due to displacement of oxygen in confined space with helium.”

Rochester Police Chief Roger Peterson on Wednesday called his manner of death “unusual,” but a funeral home worker said he’d seen it before.

An employee with Rochester Cremation Services, the funeral home that responded to the hotel, said he helped remove Smith’s body from his room and recalled seeing a tank.

The employee, who spoke on the condition he not to be identified because of the sensitive nature of Smith’s death, described the tank as being similar in size to a propane tank on a gas grill. He did not recall seeing a bag that Smith would have placed over his head. He said the coroner and police were there and that he “didn’t do a lot of looking around.”

“When I got there and saw the tank, I thought, ‘I’ve seen this before,’ and was able to put two and two together,” the employee said.

An autopsy was conducted, according to the death record. The Southern Minnesota Regional Medical Examiner’s Office declined a Tribune request for the autopsy report and released limited information about Smith’s death.

The Final Exit Network, a Florida-based nonprofit, provides information and support to people who suffer from a terminal illness and want to kill themselves.

Fran Schindler, a volunteer with the group, noted that bestselling book “Final Exit,” written by Derek Humphry in 1991 and revised several times since, explains in detail the helium gas method.

“Many people obtain that information from his book,” Schindler said. “It’s a method that has been around for many years and is well known.”

Smith’s remains were cremated in Minnesota, the records said. He was married to Janet L. Smith and had three children and three grandchildren, according to his obituary. Tribune calls to family members were not returned.

His obituary said Smith was involved in public affairs for more than 60 years and it heralded him as a “quietly generous champion of efforts to ensure a more economically and politically secure world.” Smith led private equity companies in corporate acquisitions and venture investments for more than 40 years. Earlier, he worked with DigaComm, LLC, from 1997 to 2014 and as the president of Peter W. Smith & Company, Inc. from 1975 to 1997. Before that, he was a senior officer of Field Enterprises, Inc., a company that owned the Chicago Sun-Times then and was held by the Marshall Field family, his obituary said.

A private family memorial was planned, the obituary said. Friends posted online tributes to Smith after his death. One was from his former employee, Jonathan Safron, 26, who lives in Chicago’s Loop and worked for Smith for about two years.

Safron, in an interview, said he was working for a tutoring business when Smith became his client. His job entailed teaching Smith how to use a MacBook, Safron said. At the time Smith, was living in a condominium atop the Four Seasons Hotel Chicago. Safron said Smith later employed him at Corporate Venture Alliances, a private investment firm that Smith ran, first out of the same condo and later from an office in the Hancock Building.

Safron, who said he had a low-level job with the Illinois Republican Party in 2014, said he had no knowledge of Smith’s bid to find hackers who could locate e-mails missing from Clinton’s service as secretary of state. In his online tribute to his former employer, he called Smith the “best boss I could ever ask for, a mentor, friend and model human being.”

Safron said he worked part time for Smith, putting in about 15 hours a week. But the two grew close, often having lunch together at a favorite Smith spot: the Oak Tree Restaurant & Bakery Chicago on North Michigan Ave. He called Smith a serious man who was “upbeat,” “cosmopolitan” and “larger than life.” He was aware Smith was in declining health, saying the older man sometimes had difficulty breathing and told work colleagues he had heart problems. Weeks before he took his life, he had become fatigued walking down about four or five flights of stairs during a Hancock Building fire drill and later e-mailed Safron saying he was “dizzy,” he said.

Smith’s last will and testament, signed last Feb. 21, is seven pages long and on file in Probate Court in Lake County. The will gives his wife his interest in their residential property and his tangible personal property and says remaining assets should be placed into two trusts.

He was born Feb. 23, 1936, in Portland, Maine, according to the death record.