"Michelle and I were absolutely heartbroken to learn about this unimaginable tragedy, and we want Jennifer to know that she is in our thoughts and prayers during this very difficult time. We also pray for the swift and safe return of her young nephew."
Hudson, at the behest of Obama, performed the national anthem at the Democratic National Convention in August.
Obama's remarks came hours after Hudson's sister, Julia, begged for the safe return of her 7-year-old son, Julian. The boy went missing following the murder of the Hudson sisters' mother and brother Friday.
"I know he's out there. Just let him go," Julia Hudson pleaded from the podium of the Pleasant Gift Missionary Baptist Church. The boy's father, Greg King, stood by her side during the emotional address.
"My greatest fear has already happened," she continued. "My greatest hope is finding my child."
The FBI has been called in to aid in the search, with the belief that the boy may have been taken across state lines.
Chicago police have a suspect in custody, Julia Hudson's estranged husband, William Balfour, 27. The child was not with Balfour at the time of his arrest. Balfour's mother told reporters her son had nothing to do with the murders.
Meanwhile, the Cook County medical examiner told E! News Saturday that an autopsy showed Darnell Donerson, 57, and Jason Hudson, 29, died of "multiple gunshot wounds." Both deaths were ruled homicides.
(Originally published Oct. 25, 2008 at 7:35 p.m. PT.)