If you click the video link in the story, Odinga himself tells the interviewer that his mother was Barack Obama, Sr.’s sister.
http://en.wikipedia.org/wiki/Raila_Odinga:
"Raila Odinga is of the Anglican faith[22] and is married to Ida Odinga (born Ida Anyango Oyoo). They live in Nairobi (but has a second home in Bondo District) with their four children—two sons and two daughters. His oldest son, Fidel, is named after Fidel Castro[23] and their youngest child, Winnie, is named after Winnie Mandela.[23]
"In a January 2008 interview, Odinga asserted that he was the first cousin of American Senator and presidential candidate Barack Obama through Senator Obama's father.[24] However, Barack Obama's paternal uncle denied any direct relation to Odinga, stating "Odinga's mother came from this area, so it is normal for us to talk about cousins. But he is not a blood relative."[25] Obama's father belonged to the same Luo tribe as Odinga. [24]"