The May 2016 email preceded a grading controversy that led to a state-ordered investigation of allegations of graduation-rate fraud in Maryland's second-largest school district.
On Monday, five DuVal employees were removed following findings that grading and graduation certification procedures were violated.
By Tuesday, the leaked May 2016 email and another from 2017 were raising questions among critics about the role of central office staff in the scandal.
The 2016 graduation rate at the Lanham school was 92.4 percent — a jump of more than 33 points from what was described on May 4, 2016.
"This is the most conclusive evidence to date that not only was central office aware, but they were pressuring these school-based employees," said David Murray, a school board member who is part of the minority bloc that urged the state to investigate and who represents the district that includes DuVal.
Murray said he finds it "completely unfair" that school-based employees "are being punished for what it appears they were pressured into doing. We have it completely backward in terms of who is being held accountable."
District officials denied the claims Tuesday, saying the leaked emails do not show that central office staff pressured DuVal leaders. The emails were cited Monday in a WTTG-TV report
Whittington, the author of the email, said in an interview Tuesday that he checks on graduation rates a few times a year and noticed DuVal's was uncharacteristically low.
"DuVal's graduation rate historically is much higher," he said.
His email discussed a school work sheet that showed 221 students were ready to graduate and the school needed 130 more students to reach its desired goal. "Can you provide further clarity?" he wrote. "How many of the 130 are you projecting to actually graduate? If you need support, let me know."
A second email, from April 2017, inquired about the school's rate again, asking the same assistant principal how many students would be eligible to graduate if community service requirements were not an issue. "You are at 28% now," Whittington wrote.
Several days after the email, the assistant principal circulated a long list of students on an email.
Whittington said he sent his 2017 email because he believed there was a technical issue and was questioning the accuracy of the number.
"It was just a red flag to me," he said. "No high school graduates 28 percent of kids. That's impossible."
School district spokesman John White said there is nothing new about setting goals for graduation rates and maintained there was no intimidation and Whittington was offering help.
"There's a difference between intimidation and checking in and offering support," he said.