Fog rises over a field in Russell County, Va., in November. (Julia Rendleman/The Washington Post)

Bobby Gobble was a janitor at Lebanon Elementary School when he began luring a boy to the custodian’s office and sexually abused him behind closed doors. Gobble later was able to convince the third grader’s family that the boy should move in with Gobble, and the abuse continued in Gobble’s home, where he slept in the same room as the boy, according to court papers.

Gobble pleaded guilty in 2014 to 150 counts of aggravated sexual battery, forcible sodomy and carnal knowledge in connection with his abuse of four boys — two of them elementary school pupils.

Although the abuse occurred behind closed doors in Gobble’s office, in a stockroom and in Gobble’s home, the boy who suffered abuse while living with Gobble claims that the school board and school personnel in Lebanon, Va., should have done more to protect him. A new lawsuit filed in federal court alleges that school employees were ill-equipped to prevent the abuse and to spot the signs that the boy was being regularly victimized.

The boy, who goes by the pseudonym John Doe in court documents, filed the $10 million federal lawsuit last month, alleging that the Russell County School Board and school personnel “turned a blind eye to Gobble’s blatant sexual misconduct against John and other male students” and “created and fostered an environment in which John and other male students were vulnerable and subjected to Gobble’s deplorable sexual abuse.”

Jim Guynn, a Salem, Va.-based attorney who is representing the board and school personnel, said he has not spoken at length with his clients about the lawsuit and could not respond to the accusations in detail. But he said school personnel cannot be held responsible for Gobble’s crimes: “I haven’t seen anything that indicates to me that any of the defendants had any idea that this was going on.”

A lawyer for Gobble, who is serving 70 years in state prison, did not respond to requests for comment.

The lawsuit centers on a fundamental question: What obligations do the nation’s public schools have to prevent and investigate sexual assault on school grounds? As attention to sexual assault on college campuses has grown, it has become clear that colleges have specific responsibilities to protect students under Title IX, a federal law that bars sex discrimination. Some experts say people are less aware that K-12 public schools have similar obligations to investigate and curb sex assault. There was a sharp rise last year in the number of federal civil rights complaints alleging that K-12 schools had mishandled a complaint of sexual assault, according to government data.

Monica Beck, a Michigan-based attorney who is representing the boy in Russell County, said Lebanon Elementary School officials violated Title IX because they failed to conduct their own investigation after they learned of allegations against Gobble.

According to the lawsuit, Principal Kim Hooker learned that the Department of Social Services was investigating Gobble after a complaint was filed. Hooker sat in when the department interviewed both Gobble and the boy; both denied anything inappropriate was happening.

While the complaint was unsubstantiated, Beck argues that the school should have conducted its own investigation. Instead, according to the lawsuit, Hooker told Gobble that “it would be ‘best’ if John did not stay after school unless he was in the after school program,” the lawsuit says. Hooker referred a request for comment to Guynn, her lawyer.

Phillip Henley, who was principal of the school when the boy was in third grade, was aware that the child had moved in with Gobble and that Gobble was taking him on out-of-state trips, according to the lawsuit. But the lawsuit says he never ascertained whether Gobble had legal custody of the boy and assumed he was a relative or family friend, according to the lawsuit. Henley did not respond to a request for comment.

The lawsuit also alleges that teachers saw signs something might be amiss but did nothing. Gobble disclosed to one teacher that his marriage had dissolved because his wife was “jealous” of the boy, and the boy’s fourth-grade teacher had observed Gobble’s “obsessive” and “overly friendly” behavior toward the child, the lawsuit states. One teacher noticed Gobble always seemed to have his hands on the child and sometimes took the boy out of class to give him money, the lawsuit says.

Although the teacher was uncomfortable with Gobble’s actions, she took no action to protect the child from his abuse, according to the lawsuit. The teacher sometimes allowed Gobble to spend time in her classroom with students, even letting the janitor bring children to the custodian’s office with him, the lawsuit says.

Another Russell County teacher also noticed Gobble’s suspicious behavior toward the boy one summer day in 2013 when visiting her classroom to prepare for the upcoming school year. The room was dark when the teacher entered, but after about 10 minutes she noticed Gobble and the boy hiding behind several stacked boxes.

Guynn, the attorney for the school board and school employees, said his clients cannot be held liable for Gobble’s crimes when everything they observed about his interactions with the boys was legal.

“It’s amazing that the plaintiffs turn around and make the allegations in those circumstances,” Guynn said. He said it appears that even the boy’s family was unaware of the abuse: “But the school ought to have known?”