Obama, Sr. committed bigamy when they married. He was still married to Kezia Aoko at the time.
This is all public knowledge.
Who knows if his tribal marriage to the first Kenyan wife was legally recognize by Kenya. Or if it occured. Hearsay is all it is based on. There have been many, many long discussions about this very topic. No one can come to a conclusion because there have been no reliable eyewitnesses (or any eyewitnesses) and no paperwork made public.
Please see my comment above.
It is not public knowledge at all.
It is said to be so; but whether it was so, and in what manner, remains to be found out, or not found out.
If the marriage was in Kenya, or there was a second wedding there, it wasn't bigamy, but rather polygamy, which is legal there, and was in '61.