Sean Lanigan’s nightmare began in January 2010, when the principal at Centre Ridge Elementary School pulled him out of the physical education class he was teaching and quietly walked him into an interrogation with two Fairfax County police detectives.

He had no warning that a 12-year-old girl at the Centreville school had accused him of groping and molesting her in the gym.

The girl, angry at Lanigan about something else entirely, had made the whole thing up. But her accusations launched a soul-sapping rollercoaster ride that still hasn’t ended.

“Emotionally, a part of me has died inside,” Lanigan said in a recent interview. “I’m physically and mentally exhausted all the time, how the whole process has been dragged out to this date. It certainly has affected the quality of life for me and my family at home.”

Lanigan remains in limbo, nearly a year after a jury’s acquittal. The Fairfax School District transferred him from Centre Ridge in a move that ultimately forced his wife to quit her job. School officials are now transferring him again. And the district has refused to pay his $125,000 in legal fees, even though Virginia law allows reimbursement for employees who are cleared of wrongdoing on the job.

Lanigan will never forget the day he was pulled from class. Shortly after the detectives questioned him, Lanigan, then 43 — a married father of three with a long history of service as a teacher, top-ranked soccer coach and neighborhood babysitter — had to tell his children he was going to be arrested.

“We try to teach them to do the right thing,” Lanigan said, “and I had to tell them that Daddy was going to jail and my name was going to be on the news. It was heartbreaking.”

That was followed by four nights in the Fairfax County Adult Detention Center.

“It was scary,” he said. “I was just wide-eyed. I’m an accused child molester. I’m thinking, ‘How am I going to last in here?’ ”

From there, Lanigan spent months in anxious exile, forced from his school, his players, his neighbors and his friends, pondering the possibility of up to 40 years in a state penitentiary.

That soon turned to relief. A jury found him not guilty after just 47 minutes of deliberation — virtually unheard of in a child sex abuse case. Jurors were outraged by the lack of evidence, with one weeping in sympathy during closing arguments.

But still the nightmare continues, as Lanigan struggles to earn back his reputation and career.

Within two weeks of the accuser’s report — without ever speaking to the girl — Fairfax detectives arrested Lanigan and charged him with aggravated sexual battery and abduction. The Washington Post is not naming the accuser because she is a minor.

Police issued a press release with Lanigan’s booking photo and home address, and the school district sent home a letter about his arrest. TV trucks descended on the school and his neighborhood, and Lanigan’s reputation took a lasting beating. Even today, the first thing that comes up in a Google search of Sean Lanigan is a Web site called “Bad Bad Teacher.”

Police declined to allow Nicole Christian, the lead detective on the case, to be interviewed for this article. Several months after Lanigan was acquitted, Fairfax prosecutors dismissed another of Christian’s child abuse cases in the middle of trial, a rarity, when the detective acknowledged that she had “misstated” some key facts in her sworn testimony.

Instead of Christian, Fairfax police allowed a former child sex abuse lieutenant to be interviewed about investigative procedures, but he was not involved with Lanigan’s case.

In addition, they released this statement from Officer Don Gotthardt, a spokesman: “There is a system of checks and balances between the police department, the commonwealth attorney and the magistrate. That system was followed, and it was determined that sufficient probable cause existed to proceed with prosecution.”

Fairfax Commonwealth’s Attorney Raymond F. Morrogh declined to comment for this article.

The Fairfax County School District declined to comment.

The parents of the accuser declined to comment.

Sean Lanigan grew up in Herndon, graduated from Herndon High School and earned a business degree from George Mason University. But he struggled to find a career until he volunteered to coach the crew team at Thomas Jefferson High School for Science and Technology.

Lanigan is a jock, a soccer fanatic, a goalkeeper with “GK” tattooed on his leg. Coaching and teaching was a way to keep sports in his life.

“I fell in love with it,” he said. “Seeing kids through and watching them develop, mature, grow into productive citizens. I come to work with a smile on my face every day.”

After working in the mortgage business, Lanigan had to return to college to earn another degree, in physical education, to get a teaching job in Fairfax. But he did it, and after working briefly at Stone Middle School in Centreville, he was placed at Centre Ridge in 1998.

“His heart was really with the kids,” said Kathy Young, a longtime sixth-grade teacher at Centre Ridge. “He’d pick kids up and twirl them. But what I really liked about Sean, as much as he liked playing with them, he’d always say, ‘Your schoolwork comes first.’ ”

In his Centreville neighborhood, where Lanigan lives with his wife and children, ages 14, 11 and 8, he was the dad all the kids loved, the carpool driver, the babysitter, the human jungle gym, with nicknames for everyone. “I have no qualms about having him around my children,” one mother said. “He makes my kids feel at ease. My son just adores him. He doesn’t understand how all of this happened.”

Lanigan has coached soccer continually, both at the youth travel level and high school at his alma mater — Herndon is unbeaten and the top-ranked team in the region. But Centre Ridge was his second home. When Young’s future son-in-law died in a fire, Lanigan arranged a fundraiser. In 2002, when the school needed a new playground, he and another teacher helped raise tens of thousands of dollars to get one built.

In December 2009, Lanigan was head of the Centre Ridge safety patrols. He received a phone call from a parent, complaining that a 12-year-old girl on patrol on a school bus was abusive to other children. Lanigan warned the girl that she would lose the privilege of being on patrol if she did not behave. Another teacher heard this exchange and told the girl she could also be removed as a news reader on Centre Ridge’s morning TV news show.

“Mr. Lanigan’s a jerk,” the girl told her friends, according to teachers and trial testimony. “I’m going to make him pay.”

After a second conversation with Lanigan about losing her patrol position, in January 2010, the girl and one of her friends began telling this story: Lanigan had picked up the accuser the day before, during “PE Pals,” in which students help clean up the gym and then are allowed to play there. The girls reported that Lanigan carried her over his shoulders into the main equipment room in the gym, briefly touching her breast and buttocks.

Once in the equipment room, the girls decided, Lanigan laid the accuser on a stack of blue tumbling mats, began massaging her shoulders, then laid on top of her and told her he would “treat her like a queen,” while the other girl stood in the doorway. The accuser said that she tried to get up, but that Lanigan pushed her down and asked where she was going. The accuser said she had patrol duty, and Lanigan then allowed her to leave.

Several witnesses said the tumbling mats couldn’t even fit in the equipment room, but there is no indication in reports or trial testimony that Fairfax police ever checked.

The accuser told her parents that she had been molested by her PE teacher, records show. Her parents contacted James Baldwin, who was Centre Ridge’s principal, the next day and he promptly called police. The case was assigned to Christian.

But Christian did not meet with the accuser or her parents. Instead, after the Martin Luther King Jr. holiday weekend, she watched from another room as Krista Davidson, a social worker from Fairfax child protective services, interviewed the accuser. Davidson, a school district investigator and another police detective had interviewed the girl’s parents beforehand.

Some experts say that interviewing a child sexual abuse victim too many times is harmful to the child and to the case. But Lanigan and his supporters say that with a man’s life in the balance, a lead detective should do a firsthand interview.

Christian, Davidson and Steve Kerr, the schools investigator, also spoke to the accuser’s friend, who corroborated her story. They spoke to two boys who also were in the gym, who said they saw nothing, Christian’s report shows. Then they spoke to two other friends of the accuser, who reported what the accuser told them.

The following day, Jan. 20, Christian and Rich Mullins, the other child sex crimes detective, told Baldwin, the principal, to pull Lanigan from his class and bring him to the office, Lanigan said.

Christian and Mullins “were very nice for the first 25 minutes,” Lanigan said. “A lot of small talk, get-to-know-you-type questions. About 25 minutes in, Detective Christian said, ‘You really have no idea why you’re here, do you?’ ”

Lanigan had no clear memory of whether he had picked up the girl eight days earlier, but said he might have. “I play just like I do with my own children,” he later told the jury. “Kids ask me to pick ’em up, flip ’em over.”

The detectives zeroed in. Did he carry the girl into the equipment room? Did he fondle her? He said no.

“They were throwing a lot of scenarios at me,” Lanigan said. “I felt like they were trying to trick me into a confession. They just didn’t take my word and call it a day.”

Lanigan stuck to his story and was released, badly shaken. Then he met with Kerr, who demanded his keys and school badge. He was suspended with pay, and Kerr walked him out to his car. Soon, his pay would be suspended as well.

“I drove off school property and just sat in my car,” Lanigan said, “stunned that this could have happened to me.”

On Jan. 29, police obtained felony charges of abduction and aggravated sexual battery against Lanigan. He was told to turn himself in at the Fairfax jail, which he did that afternoon.

Lanigan had no experience with jail, and he was warned to keep a low profile in light of the charges against him. He was put in a holding cell where the lights are on 24 hours a day.

“I just tried to avoid eye contact,” he said. “I realized I was in more or less a mental ward,” the protective custody wing where those who are a danger to themselves or others are held.

After a preliminary hearing in which the accuser and her friend both recanted the claim that Lanigan had laid on top of her, a judge still sent the case to a grand jury for indictment.

Lanigan’s attorneys met with Morrogh, the county prosecutor, and asked him to dismiss the case. Morrogh refused.

Lanigan fired his lawyers and hired Peter Greenspun, a veteran of emotional and high-profile cases such as that of the D.C. sniper John Allen Muhammad.

Meanwhile, Lanigan’s family was having trouble making ends meet. He wasn’t receiving a paycheck. He wasn’t allowed to coach soccer, his true love, or drive the carpool to school with the neighborhood kids.

“I wasn’t allowed to be alone around any other children,” Lanigan said. He had to meet every week with a probation officer who specializes in sex offenders. “I felt like a prisoner in my own home.”

Lanigan wasn’t working. He wasn’t coaching. And he was facing 40 years in prison.

But neighbors brought meals, every day in the first two weeks. People sent random checks by mail, or gift cards to the grocery store. Supportive e-mails poured in. “That’s what got me through the spring — the amount of support,” Lanigan said. “It’s just amazing how many people stepped up.”

Although supporters were filling a Facebook page, online detractors appeared, too. “I was afraid for my family’s safety,” Lanigan said, “based on some of the things posted to the blogs.”

As the trial approached, Fairfax Assistant Commonwealth’s Attorney Katie Pavluchuk offered a deal: Plead guilty to misdemeanor assault — no sex offense, no jail time. Lanigan refused.

“I was really excited,” Lanigan said. “I wanted the truth to come out. I wanted my life back.”

On the witness stand at trial, the accuser wore a white hooded sweatshirt over an oversized “Washington” T-shirt. Her long black hair fell frequently into her face, and sometimes she sank so low in her chair that jurors couldn’t see her.

She repeated her story about Lanigan picking her up, carrying her into the equipment room and laying her down on the mats.

She testified that Lanigan told her he would “treat her like a queen,” which is a line from a song by one of her favorite rock groups, the Ataris.

Greenspun gently cross-examined, and she admitted a history of bullying younger children, her conflicts with Lanigan and her Facebook posting that “it was a joke.” The girl also acknowledged she was mad at the gym teacher for not playing her favorite music in PE class.

“Did you tell other kids you hated Mr. Lanigan?” Greenspun asked.

“Yes,” the girl replied.

“You hated him before this happened?”

“Yes.”

Lanigan took the stand in his own defense: “I scooped [the accuser] up by her knees, put my hand on her back, just spun her around, ‘whooo’ and put her down.”

Greenspun asked, “Did you ever take [the accuser and her friend] to the large equipment room?”

“Absolutely not,” Lanigan said.

“I love kids,” Lanigan told the jury. “I’ve tried working in the real world. Teaching and coaching is my life.”

“Did you grope or molest this child?” Greenspun asked.

“No.”

The closing arguments had barely ended when jurors rendered their not-guilty verdicts.

“It was an easy decision, and we were all in agreement,” juror Asman al-Ghafari said. “I just hope Mr. Lanigan can get his life back.”

“There was no evidence,” said Jacklyn West, who wept in the jury box as the lawyers made their closing arguments, later explaining that the 12-year-old accuser “had no idea of the consequences” of her allegations. “This poor man. That’s why I cried.”

Virginia’s public soccer leagues immediately reinstated Lanigan as a coach. But the Fairfax school district was much slower. It waited three months, until just before the start of the school year, to decide that Lanigan could not return to Centre Ridge. He was transferred to South Lakes High School in Reston, and given a part-time job, teaching five out of every 10 days, though he was paid a full-time salary.

His wife couldn’t work because South Lakes was far enough away to deprive Lanigan of his role in watching and driving their children. She had to take up the slack.

Despite the acquittal, the district began an internal reprimand process. And in December, as Lanigan pushed to have his legal fees reimbursed, the district presented him with two pages of specially tailored “guidelines and expectations.”

“Do not touch FCPS students as a means of greeting, playing with, showing approval of, or otherwise interacting with them,” the guidelines state. “Avoid placing yourself in close physical proximity to any student, particularly in a manner that could be interpreted as sexual. . . . Do not be alone in your office or other rooms with a student unless the door is open and you and the student are visible from outside the room.”

Bill Cummings, a longtime friend and supporter of Lanigan, said: “They are so fixated on him being guilty that they’re pushing to put the set of expectations in his file, so he could inadvertently trip on one of them and cause them to dismiss him. They can’t see that everyone knows him as an honest and decent man.”

In March, the school district offered to pay $60,000 of Lanigan’s fees, less than half, if he would waive any future legal claims. And last month, he was “de-staffed” from South Lakes, meaning that he must apply for a job at other schools in the district.

“I just hope that one day I can put this whole mess behind me,” Lanigan said, “and outlive the dark cloud over my name and reputation from this false allegation.”