The principal of the city's second-largest high school is under investigation for allegedly hiring uncertified teachers and then underpaying them. NY1's Education reporter Lindsey Christ filed the following report.

For three years, most city schools have been under a hiring freeze, meaning when a spot opens up principals can usually consider only candidates already working in the school system. Now, one school leader is under investigation for what looks like a scheme to get around the rule.

The Department of Education is looking into whether Fort Hamilton High School's Principal Jo Ann Chester hired substitutes and had them teach classes long-term in the Bay Ridge school without being certified, as required.

The story, which first broke on the website GothamSchools.org, says at least 14 teachers may be involved.

Hiring substitutes to work full-time jobs not only skirts hiring restrictions but can also save schools a bundle.

Short-term substitutes get $155 a day, which would add up to about $28,000 a year. That is significantly less that the $45,000 first-year teachers make, and the substitutes do not get benefits. That is why they are supposed to get a salary bump and benefits after 30 days.

But at least two teachers at Fort Hamilton filed formal complaints saying although they were working full-time for months, they stayed on the books as subs.

The teachers union says the Department of Education agreed to pay both of them thousands of dollars in back pay, money that will come out of Fort Hamilton's budget.

The school is already under investigation for a different problem. In February, the DOE said an audit found Fort Hamilton staff members may have been manipulating students Regents exam scores.

Despite repeated attempts, NY1 was unable to reach the principal for comment. It is still unclear when the investigations will be complete or what will happen when school starts in September with the more than a dozen teachers impacted by the scheme.