While teaching at another school, the man had sent naked pictures of himself to the girls and written several sexually-charged text messages, writes the Barometer newspaper.
The girls promptly reported the incident, which took place in 2005, but the investigation stalled.
The man confessed to the crimes in March of last year and accepted a fine equivalent to 80 days pay.
But before police had concluded their investigation, the man had applied for another job at a new school in a different location.
As a part of the application for his new job, he was required to submit a copy of his criminal record.
But because the crime had not been fully investigated by the police, there was no record of it in the registry.
It was only after the police were able to move forward with the investigation that administrators at the new school learned of the teacher's criminal past.
According to the principal, an action plan has been drawn up with the teacher to ensure that what happened at his former school doesn't happen again.
The man will most likely be able to keep his new job, according to the principal.
However, the principal couldn't say whether the man would have been hired initially had officials been aware of his background.