Library staff closes the book on missing money mystery after patron leaves $1,200 in novel she returned

Book stackers at a Staten Island library found themselves in the middle of a mystery worthy of a best-selling novel.

Librarian Sydel Vergara was putting books away at the Mariners Harbor branch earlier this month when she noticed a thick envelope stuck between the pages of an obscure page turner.

She looked inside the unsealed envelope and found more than $1,200 in cash.

The city’s public libraries had long ago done away with overdue fines, and although their customer service was good, Vergara knew it wasn’t a tip.

So she contacted the branch manager, who reached out to the New York Public Library’s security division, and together they hatched a plan to return the missing money.

“It was a pretty thick envelope,” said Elizabeth Smith, the branch manager. “The book didn’t fully close. We said, ‘Oh, there’s something in there.’ It had a receipt. It looked like it might have been a withdrawal.”

Vergara and Smith saw a partial name on the envelope and forwarded it to William McLaughlin, the library’s assistant director of security, along with details about the book, “Thrice the Brinded Cat Hath Mew’d,” which, fittingly, is a mystery thriller.

It didn’t hurt that McLaughlin was a retired detective sergeant who had spent 20 years unraveling far more complex cases for the NYPD.

He knew that patrons who put in requests can borrow books from other branches, and he traced the likely borrower to the library’s Ephiphany Branch at E. 23rd St. on Manhattan’s East Side.

McLaughlin used every trick in the book and learned that the patron was a 73-year-old woman with no cell phone or email address. The former detective reached her on a landline, identified himself, and asked if she had misplaced anything recently.

“I guess she thought we were looking for the book,” he said.

The woman told him about the missing cash, and when she confirmed the amount, the grizzled detective made her cry.

“We have your money,” he said.

The woman, who does not want to be identified, was overjoyed.

“I thought it was lost forever,” she told him, and chalked the incident up to a senior moment.

The woman had withdrawn the money to help pay her rent and other bills, he said. She even went to church and prayed that she’d get the money back.

McLaughlin met the woman near her apartment building, and after he checked her identification — you can’t be too careful, he said — he gave her the cash and invited her into his car to count it.

“I didn’t want her counting the money on the street,” he said.

The grateful woman came bearing thank you gifts: a sandwich for him and roses for the librarian and the branch manager.

“My local library staff are unfailingly patient and helpful on my weekly visits,” the woman said in a statement. “Elizabeth Smith is an outstanding library hero to me for honesty above and beyond the call of duty. She restores my faith in the compassion and caring of the individual and reinforced my trust in the staff at The New York Public Library.”

McLaughlin said he ate his sandwich right there in the car before he brought the flowers to Staten Island.

“You don’t really get that from that many people,” McLaughlin said. “It was almost like I really knew her. We definitely developed a little rapport with each other. It was a happy ending.”