Making a trip to the nation’s capital, David Cook took part in the 2012 Race For Hope in Washington D.C. on Sunday afternoon (May 6).

The former “American Idol” winner participated in the 5K race that took place near Freedom Plaza in honor of his brother that passed away from a brain tumor in 2009.

Taking to his Celebrity MySpace page in the wake of his brother's passing, David Cook penned a thank you message to all of his supportive fans.

Just one day after Adam Cook, 37, died of brain cancer, his "American Idol" winning sibling writes: "My brother never wanted his illness to affect others. That was evident in the fact that he wanted his illness to have no part in my experience on Idol, a point he was quite adamant about. So, with that wish in mind, I ran and was involved with the event as an homage to him."

Failing to find lasting love, "American Idol" winner David Cook and former contestant Kimberly Caldwell have called an end to their romance.

"They didn't want to make a big deal about it," an insider tells of the breakup, which reportedly took place just before Christmas.