(CBS) — Four soldiers from an Indiana-based National Guard unit, including two from the Chicago area, have been killed in Afghanistan.

One of the fallen soldiers, Spc. Christopher Patterson, grew up in Aurora in a military family. The 20-year-old was attending Valparaiso University when he joined the Indiana National Guard.

Patterson’s unit, the Valparaiso-based 713th Engineer Company, was on active duty in Afghanistan when their vehicle struck a roadside bomb.

“Chris didn’t have to go with his unit when it activated,” his mother, Mary Patterson, told CBS 2 on Saturday. “When they got news that the unit was being activated he said, ‘I have to do this. I didn’t sign up to just stay in school or to get an education. I did this for my country.’”

Also killed was Spc. Brian Leonhardt, 21, of Merrillville, Ind.

Staff Sgt. Jonathan Metzger of Indianapolis and Spc. Robert Tauteris Jr. of Hamlet, Ind. also died.

Another soldier, Pvt. Douglas Rachowicz from Hammond, Ind. was injured in the blast. He suffered a broken pelvis and collapsed lung.

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