A Nigerian, Daniel Adekunle Ojo, has been arrested by the FBI in Durham, North Carolina and charged with fraud and identity theft offences.

Ojo had allegedly been using a phishing scheme, using an AOL and Gmail accounts that targeted school districts in Connecticut and Minnesota in an effort to get employees’ personal information and file bogus tax returns.

His arrest was announced on Friday by the FBI.

Following his arrest at his Durham residence, Ojo appeared before a U.S. magistrate judge in Greensboro, N.C., and was ordered detained pending his transfer to the District of Connecticut.

Prosecutors said a school district employee in Glastonbury, Connecticut, received an email in February that appeared to be sent by another employee, who asked for tax information for 1,600 school district workers. The worker who received the email then forwarded the information, which was used in the scheme to file 122 bogus tax returns seeking nearly $600,000 in refunds, authorities said.

Officials said the Internal Revenue Service processed about six of the fake returns and electronically deposited nearly $37,000 in refunds to various bank accounts.

Investigators linked the email sent to the employee to Ojo, prosecutors said.

Officials also believe Ojo was involved in similar email schemes targeting school districts in Groton, Connecticut, and Bloomington, Minnesota.

In March, a Groton school employee emailed tax information of 1,300 employees in response to an email that appeared to be from the superintendent of schools.

Authorities said the information was used to file about 66 fraudulent tax returns seeking about $364,000 in refunds. Officials said the fake returns weren’t processed because they had been flagged as being part of an identity theft scheme after school employees discovered the problem.

Prosecutors also said they linked the email account used by Ojo to a similar scam that obtained tax information for about 2,800 school employees in Bloomington earlier this year.

A federal public defender in North Carolina, Eric Placke who represented Ojo only for his initial court appearance, declined to comment on Friday.

Authorities allege that Ojo entered the U.S. on a visitor’s visa in May 23, 2016, and failed to depart on his scheduled departure date of June 8, 2016.

Ojo has been charged with conspiracy to commit wire fraud, an offense that carries a maximum term of imprisonment of 20 years, and aggravated identity theft, an offense that carries a mandatory consecutive term of imprisonment of at least two years.