The fall of Covenant House founder Father Bruce Ritter was an omen of the sexual-abuse cases involving hundreds of Roman Catholic priests and tens of thousands of victims all over the world.

Yet when Ritter was forced out in the winter of 1990, following a courageous exposé in The Post, few in the city could guess how widespread the problem was.

For 18 years, Ritter was considered a hero for how he ran the charity he founded for wayward, homeless youths. Then, several young men claimed he had sexual relationships with them and illegally used nonprofit Covenant House funds to lavish them with money and gifts. He was given a slap on the wrist: Manhattan prosecutors made him quit, but did not charge him.

When the Ritter scandal was first broken by The Post in 1989, priest sex-abuse stories were rare in the United States and unheard of in New York.

His story differed from today’s church cases in that “the secular powers more than the archdiocese or the Franciscans protected him,” says Charles M. Sennott, the former Post reporter who at age 26 broke the story of the district attorney’s probe in December 1989.

Sennott, who founded and runs the Boston-based journalism advocacy and educational GroundTruth Project, said, “The story didn’t get at the deeper truth of coverups going on in one diocese after another” — because Covenant House belonged not to a diocese, but to the Franciscan order, a worldwide community of Roman Catholic priests founded by St. Francis of Assisi in the 13th century.

But Ritter enjoyed a similar coverup for the same reasons that other charismatic clerics with cult-like followings do: unwillingness to blow the whistle on deviant priests who reel in money and garner political prestige under a veil of saintliness.

It took a young journalist to bring Ritter to heel, if not to justice. As Sennott related in his gripping 1992 book, “Broken Covenant,” it all started with an order from his boss to “pick up on six.”

He was a corporate St. Francis of Assisi - Charles M. Sennott

Ritter founded Covenant House in 1972 as a small facility for homeless teens in the crime- and drug-ravaged East Village. But the strong-willed, intellectually brilliant and domineering priest eventually grew Covenant House into a charitable giant with 178 locations in the US, Canada, Mexico and Central America.

By 1979, its flagship shelter near Times Square was “emblazoned with a three-story symbol [of a dove in hand] painted in blue” flying above rooftops.

Ritter’s belief in raising funds from private enterprise rather than from government made him seem the “perfect mix of free enterprise and compassion,” Sennott recalls.

President Ronald Reagan named Ritter one of America’s “unsung heroes” in his 1984 State of the Union Address. Covenant House subsequently more than tripled its annual budget from $27 million in 1985 to $90 million in 1989.

“He was a corporate St. Francis of Assisi,” Sennott said.

Ritter wielded the levers of power with an air of papal infallibility. In 1987, he outfoxed then-Mayor Ed Koch to take control of an old Greenwich Village union building that Koch wanted to use as a prison but where Ritter planned to house 800 homeless kids.

TV cameras focused on Ritter, then 62, standing next to First Lady Barbara Bush at President George H. W. Bush’s 1989 State of the Union Address. By that year, Covenant House’s board was a who’s who of financial and media clout.

It included captain of industry Peter Grace, financiers Teddy Forstmann and William Simon, Woman’s Day magazine editor-in-chief Ellen Levine and high executives of IBM, Chase Manhattan Bank and Bear Stearns.

But Ritter ran Covenant House virtually unchecked. Church officials and the organization’s insiders ignored years of buzz about his relationships with boys and a mysterious, secret “safe-house” program for certain youths who were Ritter’s favorites.

In October 1989, Post metropolitan editor John Cotter told Sennott to pick up a call. A former male prostitute named Kevin Lee Kite told Sennott about his long-term sexual relationship with Ritter. It wasn’t a crime — Kite was 25, although he claimed to be 19 — but Kite had much more to tell. In exchange for sex, Ritter had paid him off with a nice apartment, a computer, a college scholarship and money to buy good clothes and restaurant dinners — an illegal use of nonprofit Covenant House’s funds.

Sennott was raised in a traditional Catholic home in Boston and didn’t want to believe the worst about a saintly idol like Ritter.

“It wasn’t easy for me,” Sennott recalled this week. “Cotter said to me, ‘What made you think it would be easy, pal? Welcome to journalism.’”

Days later, Kite showed Sennott paperwork to substantiate his claims, including receipts for the funds Covenant House lavished on him.

Kite told counselors at St. Luke’s-Roosevelt Hospital Crime Victims that his liaisons with Ritter started when the priest met him years earlier in New Orleans and brought him to New York with the promise of leading him to a new life. But it turned out to be another form of prostitution, Kite learned: sex in exchange for money and goods. Ritter’s hypocrisy also infuriated him. While on a panel set up by US Attorney General Edwin Meese to “study” pornography, Ritter publicly warned that the genitalia on Michelangelo’s David sculpture could provoke dangerous sexual desires.

Kite’s next stop was the office of Manhattan District Attorney Robert Morgenthau. Morgenthau’s famed sex-case prosecutor, Linda Fairstein, gave him a tape recorder to catch Ritter discussing sex and money with him.

Prodded by Cotter, who warned the reporter, “I’ll kick your ass” if he got beat on the story, Sennott pursued the scoop. He learned from sources that the DA had put Kite into a “witness-aid program” for his protection.

On Dec. 6, a nervous but determined Sennott reached Ritter by phone. The priest denied all the allegations to Sennott and suggested he, Ritter, was being “set up” by “organized crime.”

Ritter’s war machine swung into action when it learned The Post was ready to go with the story.

Cotter and executive editor Jerry Nachman came under siege by Covenant House board members, advertisers, Gov. Mario Cuomo, Rep. Geraldine Ferraro, and pressmen’s union President Jack Kennedy, who was the brother of Ritter’s physician and Covenant House board member, Dr. Jim Kennedy.

Sennott’s book relates that Covenant House’s pit-bull lawyer, Stanley Arkin, warned Nachman, “This is sleazy and steamy. You better be damned careful.” Tough-as-nails Nachman responded, “Counselor, I don’t know what you are talking about. We are running a story about a defalcation” — legalese for embezzlement.

The Post’s front page on Dec. 12, 1989 shouted, “TIMES SQUARE PRIEST PROBED Former male prostitute cites ‘gifts.’” Based not on Kite’s word, but entirely on the facts of Morgenthau’s investigation, the story made no mention of sex with Ritter, except for one detail: Morgenthau had assigned the case to his Sex Crimes Unit.

In the tumultuous weeks following, The Post was accused of trying to destroy an iconic, beloved priest in order to sell papers.

Ritter’s team put Kevin Kite’s estranged father on TV to state that his son had a “history of lying.” When the investigation seemed stalled, The New York Times editorialized that Morgenthau was subjecting Ritter to a “slow bleed” that could be “ruinous” to Covenant House and its good works.

Columnists at the Times, the Daily News and Newsday all stuck up for Ritter. TV’s “Inside Edition” did a story titled “Anatomy of a Smear.” John Cardinal O’Connor, the powerful head of the New York Archdiocese, said, “I have held Father Ritter’s work in the highest esteem.”

The Post stuck by its guns. Soon, other young men who’d shared Ritter’s bed found their voices. In early February 1990, four of them told their stories to The Village Voice and the Times. It turned out that Ritter had sex with at least 15 young men at Covenant House, one of whom was 14 at the time.

The archdiocese stepped in to help broker a deal between the DA and Ritter. Morgenthau wouldn’t charge him, but he had to quit Covenant House and never work with young people again.

Ritter fought to keep a role at the organization after “temporarily” stepping aside on Feb. 6. Three weeks later, fearing that the DA would send the case to a grand jury, Ritter gave up and skulked off to his upstate home.

There was anger that he escaped prosecution. One of Ritter’s victims, Darryl Bassile, wrote to him in March 1990, “You were wrong for inflicting your desires on a 14 year old . . . I know that someday you will stand before the one who judges all of us and at that time there will be no more denial, just the truth.”

Father Ritter died in obscurity at his farmhouse in Otsego County on Oct. 7, 1999.

Covenant House survived under new leadership, and continues to serve homeless and runaway youth.

Since Ritter’s fall, predatory priests have since been found to have abused thousands of children and young men in New York, Washington, DC, Pennsylvania, Australia, Chile and Ireland. The church has paid out billions of dollars in settlements — including $60 million by the New York Archdiocese in the past two years, The Post reported this month.

Now Italian Archbishop Carlo Maria Viganò charges that Pope Francis has known since June 2013 that former Washington, DC, Archbishop Theodore McCarrick was a “serial predator” but covered for him until an investigation forced McCarrick out in June. The pope unsatisfyingly responded, “I will not say a single word on this.”

It’s a pity that the church didn’t learn from the lesson of Father Bruce Ritter — that the truth will come out eventually, even if it’s too late to erase the suffering.