Even though Derwin Williams had spent a year in Iraq in 2004 with the Illinois National Guard, his current tour in Afghanistan was much more grueling. He was ready to return home with his unit next month.

Williams, 41, who worked as a correctional officer with the Cook County sheriff’s office, was killed Monday when his vehicle hit a roadside bomb in Kandu, said his wife, Felicia.

Williams, of Glenwood, who was leading a five-vehicle convoy with the 33rd Infantry Brigade Combat Team, was one of four people in the vehicle who died, his wife was told Monday evening.

An Illinois National Guard spokeswoman would not comment, but the sheriff’s office said in a statement that Williams was the second correctional officer with the department to be killed while on duty with the Guard.

“He said Iraq was nothing like Afghanistan. It was just terrible,” his wife said. “He just told me he couldn’t wait to come home, he couldn’t wait to get out of [Afghanistan]. He wouldn’t elaborate.”

She said the men, who were assigned to guard a nearby base, were training a group of soldiers to take over their role after they returned home.

She said her husband had been deployed to active duty in August and had been in Afghanistan since September. She said he had started with the Guard in 1993.