Contacos-Sawyer said organizations should perform human resources functions, including hiring and fact-checking resumes, from a centralized office, rather than distribute the responsibility to managers such as principals.

"It's best for principals to be in charge of what they do best," she said. "Let the HR professionals do what they do best."

Nowlin was arrested and charged with second-degree rape, sex abuse of a minor and second-degree assault in connection with a Harford County teen he was counseling. The teen is not a student at Hazelwood.

Prosecutors said Nowlin had legal guardianship of the teen, which he was able to obtain because he misrepresented himself as a therapist. During an investigation, prosecutors said, they concluded he was a hall monitor.

Nowlin and his attorney have declined to comment on the charges and his credentials. Nowlin's attorney said his client maintains his innocence.

According to online court records, Nowlin pleaded guilty in 2006 in Baltimore County District Court to theft of more than $500. Details of that case were unavailable late Friday.

According to parents, prosecutors, community members, school officials and social media, Nowlin represented himself in a variety of capacities: as a child and family therapist, licensed social worker, guidance counselor, vice principal, dean of students, dean of student support and director of community affairs.

In August, Nowlin signed a $24,900 contract as a "life skills education facilitator" and director of student support, and his duties were to "provide structured support to emotionally disturbed students in crisis."

According to school officials, he earned $17,796 of the contract — which was to expire June 29, 2013 — between August and November.

The minimum qualifications for the job include a doctorate in social work or a licensed clinical social worker degree.

On the contract, signed and dated by Nowlin and the school's principal Aug. 20, Nowlin identified himself as a doctor and licensed social worker.

Online records with the Board of Professional Counselors & Therapists, Board of Social Work Examiners and Board of Physicians show that he is not licensed in Maryland.

Several parents said Nowlin told them that he had received a doctorate from the Johns Hopkins University this past spring, though Hopkins officials said they haven't had a graduate or a student by that name.

A Facebook page under his name indicates Nowlin attended Howard and Hampton universities. Officials at both schools said they haven't had a student or graduate by that name.

City school officials declined to release Nowlin's resume Friday because it was part of his personnel file.

A "School Improvement Plan" — a 94-page document outlining extensive measures for raising achievement at Hazelwood — published by the school system in 2011 listed Nowlin as the director of community affairs and acting guidance counselor.

According to a job posting by the system, a guidance counselor requires a master's degree and must be certified as a guidance counselor by the state.

Baltimore Sun reporters Yvonne Wenger and Jean Marbella contributed to this article.