Several parents said that Nowlin told them that he 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 that Nowlin attended Howard and Hampton universities. Officials at both schools said they haven't had a student or graduate by that name.
Nowlin and his attorney have declined to comment on the charges and his credentials. Nowlin's attorney said his client maintains his innocence.
Citing personnel policies, the school system would not provide Nowlin's resume, though he was last employed as a contractor. Documents related to contractors, including their credentials, are usually public information.
"What we have to acknowledge is that he defrauded all of us — if the allegations are true," Edwards said.
Edwards said that the system will implement a dual credential-check protocol for all new hires, which would require that principals check qualifications and then submit names to the school system's human resources department for vetting.
Edwards said that while the district will not make sweeping or punitive overhauls as a result of the Nowlin case, it is working to ensure that guidelines strike the right balance, not being obstructive but strong enough to help school leaders make the best judgment.
She did say, however, that the district would stress to principals that "with flexibility comes responsibility."
Jimmy Gittings, president of the city principals union, said the union "will work with central office to ensure that our administrators are very clear about district hiring rules.
"[We] share the district's commitment to ensuring every person working in a school has the qualifications necessary to support the academic and social needs of our children," Gittings said. "It is important that principals maintain the appropriate level of flexibility around hiring, because they are ultimately responsible for student achievement."
The system said it is reviewing its current policies on temporary employees, some of which appear to conflict with Nowlin's tenure.
According to the district's policies, all temporary employees must be cleared by the district's human capital department.
Edwards said that while the central office did approve his employment, the problem occurred when he began taking on roles beyond what he was hired to do, and no one alerted the system.
The policy and guidelines also state that temporary employees can only stay in that status for 90 days, and Nowlin's official title of "Temporary II" included mostly classroom-related positions.
School officials acknowledged that Nowlin was incorrectly classified, though his salary scale was appropriate. Officials also granted the principal's request to allow Nowlin to surpass the 90-day mark — a common practice if principals can make a case for an extension.
Salary records dating to 2008 show that some temporary employees have been in that status for up to four years, an issue the school system acknowledged it hasn't addressed.
"This isn't a Shawn Nowlin issue, this is a temporary professional issue," Edwards said. "We need to have the conversation, and it needs to be more rigorous."