The second-highest ranking official in the Florida Highway Patrol is resigning amid an ongoing review into whether troopers were being ordered to meet traffic ticket quotas.

Lt. Col. Michael Thomas resigned Monday after it was discovered he sent an email in late May that encouraged troopers to write two tickets an hour. Thomas had been with the Florida Highway Patrol for 30 years. His last day on the job will be Sept. 1.

In his resignation letter, Thomas said the email was a “grave error” and could have been interpreted as an order to supervisors.

This is the second resignation this month. Maj. Mark Welch of Tallahassee’s Troop H resigned after he told troopers they weren’t writing enough tickets.

Top state officials have insisted that ticket quotas are not allowed.

(AP)