HELENA - Teen boys at a private residential treatment center north of Condon are at times verbally abused and subject to harsh discipline and seclusion by largely unqualified staff, a state investigation has concluded.

The allegations are among 19 licensing violations found by the state Department of Public Health and Human Services during a monthlong investigation of the Swan Valley Youth Academy late last year.

The probe was sparked by a letter from Andree Larose, a Montana Advocacy Program attorney who alleged physical and verbal abuse, as well as licensing violations. She is representing a former academy resident.

The military-style facility, which is licensed by the state health department, is cooperating and preparing a response, said the agency’s Julie Fink, who prepared the investigation report.

She called the number of violations lengthy for a youth care facility, and said Swan Valley’s license could be revoked if an agreement to fix them cannot be reached.

‘‘Obviously, when the deficiencies are the number they are, it surprises us,’’ Fink said Thursday.

Swan Valley’s acting director was unavailable for comment Thursday. Joe Newman, who helps run the Colorado-based company Cornerstone Programs that opened the academy in 2000, did not immediately return a phone call seeking comment.

Swan Valley is under contract with the federal Bureau of Prisons. The 100-acre facility accepts boys ages 13 to 18 who are referred through the court system, the academy’s Web site states. They generally stay six to 12 months, attending classes while undergoing therapy and chemical dependency treatment if needed.

The academy’s Web site states it uses a ‘‘military therapeutic model’’ to provide ‘‘structure, discipline and integrity.’’

In the licensing report, investigators said a staff member told them the program’s philosophy is to ‘‘break the kid down to build them up,’’ a view they called ‘‘particularly harmful to any child’s well-being.’’

Teens are often degraded and yelled at by staff members and many have vomited when forced to do excessive exercise and drink large amounts of water during intake, the report stated. Child abuse and neglect concerns have not been reported as required, and the facility also failed to report a suicide attempt, according to the investigation.

Swan Valley is also accused of keeping teens in seclusion for too long, some for several days, and verbally abusing them by calling them names and making ‘‘negative comments about the resident’s family,’’ the report stated.

Investigators also said the facility lacked a licensed psychiatrist or psychologist and concluded several staff members were not qualified to work in group child care. Swan Valley counts military service toward such experience, but investigators said that was not relevant.

‘‘(Treatment professionals) are key in addressing kids who are involved in the youth court system,’’ Larose said. ‘‘Especially since they bill themselves as a treatment program, to not have any treatment professionals was a significant violation.’’

Larose said she was pleased with the licensing investigation, which mirrored many of her own findings. Neither she or the health department would confirm a separate abuse investigation by the state, saying such inquiries are confidential.

‘‘What’s going to be key is what is the corrective active plan and is it enough to change a culture at the facility?’’ Larose said. ‘‘There’s going to need to be some vigilant follow through.’’