MONROEVILLE, Ala. » One morning late last summer, Tonja B. Carter was doing some legal work for her prized client, Harper Lee, when she found herself thumbing through an old manuscript of what she assumed was "To Kill a Mockingbird." The characters were familiar, as they would be to millions of readers – the crusading lawyer, Atticus Finch, and his feisty daughter, Scout. But the passages were different. Atticus was much older. Scout was grown up. The story unfolded in Alabama during the racial turmoil of the 1950s, not the Depression of the 1930s.

Confused, Carter scanned the text, trying to figure out what she was holding. It was a novel titled "Go Set a Watchman." It may be one of the most monumental discoveries in contemporary American literature.

"I was so stunned. At the time I didn’t know if it was finished," Carter recalled in an interview Saturday, her first extensive comments about the discovery. She went to see Lee and asked her if the novel was complete.

"She said, ‘Complete? I guess so. It was the parent of "Mockingbird."’"

The recovered manuscript has ignited fierce debate – much of it speculative – about why Lee waited so long to publish again, whether the book will stand up to her beloved first novel, and whether the author, who has long shied away from public attention, might have been pressured or manipulated into publishing it.

And as word of the new book spread in her hometown, the fog that long shrouded the enigmatic, publicity-shy author – known to most as Nelle – has only deepened.

Some close friends were shocked to hear of a second novel from Lee, who was often emphatic that she would never publish another book. But others in her inner circle long knew of its existence. At least one family member remembered reading portions of the manuscript for "Go Set a Watchman" in the mid-1950s.

"It definitely was her writing, and it was never lost," Hank Conner, Lee’s oldest nephew, said in an interview. "It obviously has been in the possession of the family."

What should have been a triumphant literary discovery – a find that could significantly add to the legacy of one of the country’s most cherished authors – quickly morphed into a puzzling controversy. While there have often been debates about works that were discovered and published posthumously, including unfinished novels by masters like Vladimir Nabokov and David Foster Wallace, it is rare for a living writer’s literary intentions to be cloaked in so much uncertainty.

Residents of Monroeville gossip that Lee is mentally infirm these days, does not recognize old friends, could not possibly have signed off on the publication, never wanted to do a second book. But those who are closest to her scoff at such conspiratorial theories, saying Lee, now 88 and admittedly frail, remains fully capable of making up her own mind.

The woman who has ignited such frenzied speculation remains tucked away in the Meadows, an assisted-living center, largely cut off from the prying public except for statements delivered through Carter, her lawyer, friend and gatekeeper.

After doubts surfaced, Lee said in statement Wednesday through her lawyer that she was "happy as hell with the reactions to ‘Watchman.’"

Answering questions Saturday through both emails and text messages, Carter said that Lee is "extremely hurt and humiliated" at the suggestion that she had been duped.

"She is a very strong, independent and wise woman who should be enjoying the discovery of her long lost novel," Carter said. "Instead, she is having to defend her own credibility and decision-making."

Others close to Lee, like two friends who visited her Saturday at the Meadows, attest to her excitement over the release of the novel.

Cynthia McMillan, a resident assistant at the Meadows who has taken care of Lee for several years, said in an interview that Lee was alert, understood what was happening with the newly found manuscript and seemed invigorated by the prospect of publishing again.

"She seems excited about it, and it has given her something to focus on since her sister died," McMillan said, describing Lee as "sharp as a tack."

Nonetheless, the skepticism remains heavy here in this town of about 6,500 residents, where Lee has kept a home since childhood and where her aura looms large. The town square features murals depicting scenes from "To Kill a Mockingbird," and for several weeks each year, residents perform a play based on the book, acting out some scenes in the local courthouse. Residents were accustomed to seeing the author clad in sweatpants and brown glasses, hunting for bargains at the Dollar General and dining with her sister Alice – by all accounts a strict protector of Lee – at the back table of David’s Catfish House.

Over the years, though, Lee developed a somewhat prickly relationship with residents, particularly those who seemed eager to cash in on her fame. She stopped signing books for local stores when she learned that some were being auctioned on eBay. In 2013, she sued the town’s museum, claiming that sales of "Mockingbird"-themed T-shirts, totes and coffee mugs infringed on her copyright. The case was settled last year.

The author’s reticence may have fueled the scrutiny over the new book, compounded by the silence, until this weekend, of Carter, and the dearth of information from Lee’s publisher, Harper, an imprint of HarperCollins. The vacuum left Harper scrambling to rebuff suggestions that Lee had been cajoled into agreeing to do something she had resisted for 50 years.

"She used to say, ‘I wrote one good book and that was enough,’" said Starling Lawrence, the former editor-in-chief at W.W. Norton and a friend of Lee’s.

Karen Hare, owner of David’s Catfish House, said that on more than one occasion, Lee was explicit that she did not intend to publish anything else during her lifetime.

"She always said she didn’t want anything done until she died," Hare said.

The Rev. Thomas Butts, who was Lee’s pastor for many years at a local Methodist church, said he was surprised that the book suddenly turned up after so many years.

"It is sort of strange it had not been found before," he said.

Some of the skeptics are longstanding friends of Lee’s who live in distant places and had not been able to speak to her of late because of her diminished hearing. Like most others, they found out through news reports Tuesday, when Harper announced the discovery of "Go Set a Watchman" and said it would be released July 14.

"I had no idea there was a book hidden away, and Nelle was always so insistent on not publishing anything else," said Claudia Durst Johnson, an author, scholar and friend of Lee’s since the 1980s. "I was surprised and a little bit worried about how much control she has."

Much of the scrutiny has settled on Carter, once an assistant at the law firm here where Harper Lee’s father and sister also worked, and where she is now a lawyer herself. Since her admission to the bar in 2006, Carter has increasingly been in charge of Lee’s affairs, offending some in town who feel she has restricted access to the author.

By many accounts, though, Carter has been a dutiful steward of the Lee sisters’ affairs.

"Tonja has the full confidence of Nelle," said Diane McWhorter, a journalist and friend of Lee’s who visited her twice last summer. "And I can say with confidence that Tonja would not do anything that Nelle would not want her to do."

Carter appears to have won the trust of Lee’s publisher, too. She was a key contact for HarperCollins as the deal for the new book was negotiated.

"We talked to her through her lawyer and friend Tonja Carter," said Jonathan Burnham, the senior vice president and publisher of Harper, adding that speaking with Lee directly "wasn’t necessary."

Carter said she was distressed by the suggestion that she would exploit Lee.

"Nothing can describe how I feel" about that, she said. Asked why she had not provided more detail about the discovery, which might have quelled suspicions, she said: "I am a lawyer, not a celebrity. The focus should be on the gift Harper Lee is giving the world."

The publisher said the manuscript had been sent to several readers for review as Lee deliberated whether she wanted to publish it. The company declined to identify those readers, as did Carter, saying, "It is nobody’s business."

Joy Brown, who with her late husband, Michael, had provided financial help in the mid-1950s to Lee so she could write "To Kill a Mockingbird," said in an interview she had no idea that the manuscript existed until January.

Brown said Carter, Lee’s agent and her publisher came over to her Manhattan home for a meeting that lasted a couple of hours.

"They did not want me to be surprised when they did announce it, and they swore me to secrecy," Brown recalled.

Fifty-five years after its publication, "To Kill a Mockingbird" remains one of the most influential works in American literature, with global sales topping 40 million copies. According to court documents, in a standard six-month period, sales of the novel brought Lee nearly $1.7 million in royalties.

The new novel will no doubt be another commercial juggernaut. Shortly after the title was announced, a surge in preorders pushed it to No. 1 on Amazon. HarperCollins is planning a first printing of 2 million copies.

"Go Set a Watchman" would have been Lee’s literary debut, if her editor had not rejected it. She finished the novel, which takes place 20 years after "To Kill a Mockingbird," in the mid-1950s. But her editor, Tay Hohoff, told her to write a new version from Scout’s perspective as a young girl.

She cast aside the original book. She said in a statement last week that she thought it was lost.

When Carter revealed her discovery to Lee in August, the author was shocked, Carter recalled. Lee immediately asked her friend to repeat herself. Carter reiterated that she had found a novel, calling the book "Go Set the Watchman." She was swiftly corrected: "It’s ‘Go Set a Watchman,’" Lee said.

Alexandra Alter and Serge F. Kovaleski, New York Times

© 2015 The New York Times Company