The police officer came for Tim Schnabel just as planned, arriving in an unmarked black Honda outside LaGuardia Airport, where he waited for him to emerge from baggage claim.

It was a first meeting between the licensed marriage and family therapist and the officer who just happened to be Schnabel’s great-nephew Rob. But there was no mistaking who he was. He looked more like Schnabel’s father, Arthur, than he did.

It was an awkward moment between family, but it wouldn’t end that way. There was still more family to meet.

The police officer, though, put Schnabel in a reflective mood. No one was to ever know this, but more than 75 years earlier, a policeman had picked up Schnabel’s father not far from here in downtown Manhattan for armed robbery.

It would take nearly his entire life to unravel that secret, but in 1990 Tim Schnabel finally did.

“I knew that something mysterious had occurred in my father’s life,” he said. “I just didn’t know what.”

Soon after his father passed in the winter of 1965, Schnabel was having dinner with his uncle Hank, when he let slip that Arthur had been married once before.

As soon as the blood drained from Schnabel’s face, his uncle knew.

“Oh my God, you didn’t know,” he said.

No, Tim Schnabel muttered, holding back tears.

His uncle quickly changed the subject. Schnabel got a similar response when he broached the subject with his mother, Jerry. It was none of his business what occurred before she and his father met.

With that, his mother eventually took the secret to her grave.

A few years would pass before Schnabel would reach out to one of his last surviving cousins in New York.

I think my father was once in trouble with the law, he told her. Is it true?

Yes, it was, she told him, but she didn’t know details.

In 1990, Schnabel wrote the Department of Correctional Services in Albany, N.Y., and the New York City Police Department.

“I gave them my father’s name and birthday and said, ‘I believe you may have known him,’” he recalled recently. “The police sent me for a fee all the records they had of his arrest. The Department of Corrections sent me what they had.”

The records showed that on May 13, 1938, Arthur Henry Schnabel was indicted on armed robbery charges. He pleaded guilty and was sentenced to six years in prison. In 1942, he was released on parole.

And there was this little gem: the name of his father’s first wife and the son she’d given birth to 12 years before Arthur Schnabel was sentenced to prison.

Arthur Schnabel wasn’t well-educated. He dropped out of school in the sixth grade, but he was a quick study. He was 25 when he joined the U.S. Army and was shipped to Honolulu, where he met his first wife.

After prison, he got a job as an orderly at Bellevue Psychiatric Hospital in New York City, where he met Geraldine Delaney, a young psychiatric nurse.

“She fell in love with a man who was 17 years older than her,” Tim Schnabel said of his mother. “He told her everything.”

He loved baseball and playing the ukulele. He was married once. He had a son. He served time in prison for robbing two foot doctors for a combined total of $85. Geraldine shared the 411 with her father, who helped him get a job at General Electric back in Massachusetts.

Their secret was safe. She and Arthur were married in 1943, and a year later Tim was born, then his sisters, Ann Marie and Judy. They enjoyed a middle-class existence in Beverly, Mass.

But the whispers at family gatherings and the unanswered questions haunted young Tim, who in 1966 would leave the coop for college and then the Peace Corps-Brazil before moving to Winston-Salem, N.C., to work as a counselor at a research residential treatment facility.

He married a girl named Nancy in 1990 and with her encouragement kept digging.

The next year, he found his half brother, who’d been given his father’s name, Arthur Henry Schnabel.

“Artie looked more like our father than I did,” he said. “In fact, when he first came to visit my wife and me in 1991, my heart stopped beating a few seconds watching him exit from the jetway.”

They met a few times over the years, but Tim Schnabel never met any of Artie’s four children or their families.

When Artie passed away last year, Tim Schnabel knew if he didn’t go see his brother’s family soon, he never would.

“I decided I wanted to meet my great-nephew Rob and his family,” he said.

And so there he was a few weeks ago on Long Island with the rest of the Schnabel family: Artie’s sons Larry and Arthur and Rob’s sister, Cortney, and brother, you guessed it, Arthur.

“It was very healing for me to do this,” Tim Schnabel said. “They actually invited me back.”

At his home in Monroe the other day, the therapist, now 71, laid bare his heart, outing the secret and the accompanying shame that has kept his family apart all these years.

“Holding on to secrets is toxic,” Tim Schnabel said. “But letting go of secrets allows us to move from shame to acceptance, knowing we are deserving of value, love and dignity. I am sure my father never wanted his children to think less of him or disown him, but he couldn’t take the chance.”