Mr. Levine did not immediately respond to a request for comment made through the Met.
The man, who grew up in Illinois, said that he had met Mr. Levine at the Ravinia Festival, the summer music event Mr. Levine led as music director from 1973 through 1993, according to the police report. The New York Post first reported details from the report on Saturday.
The man told the police that he was a music lover with dreams of becoming a conductor who had been four years old when his parents first took him to meet Mr. Levine at Ravinia. He told the police that the misconduct began in the summer of 1985, when he was 15 and Mr. Levine was in his early 40s. He told the police that Mr. Levine drove him home and, in the driveway of his family’s home in Kenilworth, “started holding my hand in a prolonged and incredibly sensual way.”
He said that Mr. Levine told him he wanted “to see if you can be raised special like me.”
The abuse escalated the following summer, the man told the police, when he would visit Mr. Levine at the Deer Path Inn, a hotel near Ravinia.
“I would get there and the lights are off, and he would say to me after I came in and after a hug ‘take your clothes off,’ ” the man wrote in a statement to police.
“On various occasions he would ask me how I touched myself and then he would touch me the way I touched myself,” the man wrote. “I was never able to be aroused by this. But then he would masturbate himself at his bed or in the bathroom.”
The police report contains a college recommendation that Mr. Levine wrote for the man on Met stationery in 1987. In it, Mr. Levine wrote that he had known the teenager for “almost fifteen years.” The man also told the police that Mr. Levine had given him money over the years, which he estimated added up to $50,000.
Peter Gelb, the general manager of the Met, said on Saturday night that the company would begin an investigation of Mr. Levine.
“This first came to the Met’s attention when the Illinois police investigation was opened in October of 2016,” Mr. Gelb said. “At the time Jim said that the charges were completely false, and we didn’t hear anything further from the police. We need to determine if these charges are true and, if they are, take appropriate action. We will now be conducting our own investigation with outside resources.”
The man told the police that the abuse went on for years, and that “this pattern repeated itself hundreds of times,” later continuing in New York City. At one point, the man wrote, Mr. Levine invited him to New York for an audition to see if he had the makings of a conductor — and concluded that he did not, and that he should focus on his other talents. “While the musical mentorship potential was over at the end of the audition, the promise of his raising me ‘special’ like him never ended,” he wrote in the statement to the police.
The man told police that he “only recently realized” that his history with Mr. Levine was affecting his life in “a negative manner.” The police report indicates that Lake Forest detectives interviewed Mr. Gelb of the Met and several journalists who have written about Mr. Levine over the years. Detective Wendy Dumont of the Lake Forest Police declined to comment when reached Saturday.
Beth Glynn, a former board member at the Met Opera, confirmed on Saturday that she had spoken with a police detective after having been called by the man accusing Mr. Levine of misconduct.
“I don’t know how he got my number,” she said in a brief phone interview. “I told him twice he must call the police and I hung up.”
Mr. Levine, 74, is among the world’s most famous and influential conductors, a star of European festivals and American orchestras alike. But his commitment to the Met is unprecedented — he has been virtually synonymous with it since he became its music director four decades ago. He has led more than 2,500 performances with the company, more than any other conductor — expanding its repertory, spurring the creation of its young artists’ program and raising its orchestra’s level to that of the world’s finest symphonic ensembles. Mr. Levine was paid $1.8 million for the 2015-16 season, according to the Met’s most recent tax filings.
But rumors about Mr. Levine and sexual abuse have also circulated for years. Johanna Fiedler, who was the Met’s press representative for 15 years, wrote about them in her 2001 book “Molto Agitato: The Mayhem Behind the Music at the Metropolitan Opera.”
“Starting in the spring of 1979, these stories came to the surface at more or less regular intervals,” she wrote. “Each time, the Met press office would tirelessly point out the cyclical nature of the gossip and the complete lack of substance.”
In 1987 Mr. Levine dismissed the rumors in an interview with the Times, recalling that he had been told years earlier that there were “reports of a morals charge in Pittsburgh or Hawaii or Dallas.”
“Both my friends and my enemies checked it out and to this day, I don’t have the faintest idea where those rumors came from or what purpose they served,” Mr. Levine said at the time.
In recent years Mr. Levine has struggled with health problems and surgeries, which caused him to resign as music director of the Boston Symphony Orchestra, after seven seasons, in 2011. He missed two Met seasons after sustaining a spinal injury that year.
He returned in 2013, but complications related to his Parkinson’s disease sometimes caused his left arm to flail and made it increasingly difficult for performers to follow his conducting. He stepped down from his position in April of 2016, becoming the Met’s music director emeritus.
Mr. Levine’s physical capacities have lately seemed to improve, and he has a robust schedule at the Met this season, already leading a run of Mozart’s “Die Zauberflöte” and Verdi’s Requiem this fall. He has jumped into a new production of Puccini’s “Tosca” set to premiere on New Year’s Eve, with Verdi’s “Il Trovatore” and “Luisa Miller” to follow in coming months.
As of Saturday night, Mr. Levine was still scheduled to conduct “Tosca” on New Year’s Eve.