I don’t believe that mix and match between tribal, Civil/Christian or Muslim marriages was allowed.
See Kenya Marriage Act of 1902 paragraph #49:
49. Whoever contracts a marriage under this Act, being at the time married in accordance with native law or custom or in accordance with Mohammedan law to any person other than the person with whom such marriage is contracted, shall be guilty of an offence and liable to imprisonment for a term not exceeding five years.
kenyalaw.org/family/statutes/...?file=The+marriage+act.pdf
How did Sr. get out of serving time?