At least one teacher at the Noyes Education Campus coached students toward correct answers on standardized tests in 2010, according to a D.C. inspector general’s report released Wednesday that found a number of testing-integrity problems at the Northeast Washington school.

Investigators for D.C. Inspector General Charles J. Willoughby interviewed dozens of school employees and parents to reach that conclusion. But there was “insufficient basis” to warrant examining other schools in the same intensive manner, according to the report, which concluded that there was no evidence of widespread cheating across the city from 2008 to 2010.

Schools Chancellor Kaya Henderson said in a statement that she hopes the report will put to rest suspicions of cheating on the D.C. Comprehensive Assessment System, which is used to measure student achievement and teacher effectiveness.

She expressed dismay, however, at the revelations about Noyes, where the teacher who admitted coaching students told investigators that it “seemed” it was “understood” that this was how testing was conducted at the school.

“It is disappointing that a handful of staff would think so little of their profession and of their students that they would do anything to compromise results,” Henderson said. “We employ the best teachers in the world. I am proud of them day after day, but the staff implicated in this report do not represent what we stand for as a school system.”

Henderson requested the inspector general’s probe in 2011 after USA Today published a story detailing unusually high numbers of erasures from wrong to right answers at Noyes and more than 100 other D.C. public schools from 2006 to 2010.

Caveon, a firm hired by D.C. public schools, also found evidence of cheating at Noyes in 2010. But the firm found no evidence of widespread cheating that year or the year before. Critics questioned whether those probes were rigorous enough to root out the truth after Caveon officials said they had not been asked to use all the forensic tools at their disposal.

Noyes had come under scrutiny for dramatic gains in reading and writing from 2006 to 2009 under then-Principal Wayne Ryan. In 2009, the school was named a National Blue Ribbon School by the U.S. Department of Education.

Ryan was promoted to a supervisory position after the 2009-10 school year. He resigned in 2011 without offering an explanation. Amid questions about cheating, Noyes’s test scores fell. From 2009 to 2011, math proficiency fell from 63 to 28 percent of students. Reading proficiency fell from 84 to 32 percent.

Willoughby and his staff examined testing at Noyes during the 2008-09 and 2009-10 school years. They interviewed Henderson, former schools chancellor Michelle A. Rhee, 32 current and former school staff members, and 23 parents of Noyes students.

None of the parents said their children had reported receiving assistance from teachers.

But the same Noyes teacher who admitted coaching students alleged that a test coordinator had instructed staff members to ensure that struggling students sat near the back of the classroom during tests. That way, the teacher alleged, test monitors peering in from the hallway would not see teachers offering help. The teacher no longer works at the school, according to the report.

The test coordinator denied the allegations.

Another teacher said copies of the test had been distributed before exam day, and teachers were told to “go over the test with students.” That teacher said the principal had prohibited monitors, whose job is to ensure test integrity, from entering classrooms.

The principal disputed the claims, but several monitors said they were told to stay out of classrooms.

Investigators said they discussed irregularities at several other schools — such as J.O. Wilson Elementary, where more than 80 percent of classrooms were flagged for high erasure rates in 2009 — with Henderson. Based on those discussions, as well as other interviews and the Caveon probes, there was not enough concern about those schools to warrant further investigation, they wrote.

An elevated number of wrong-to-right erasures is not by itself evidence of cheating, they added.