Looking on how to find runnaway slave information if i can

i am researching my Durrs i have come to find that my earliest John Edward Durr might of possibly of had a slave mother and slave owner father he was born in south carolina 5 may 1828 i don't have anything from south carolina that prooves this only information i have is from his death registar in ontario canada and three censuses that say he's from south carolina he moved to canada sometime around 1852 according to the canadian census 1901
He Married in Canada to a native canadian or english her name was Diana Larkin d/o William Larkin and Pheobe Laurence(Lawrence) they married feb 1856 Had 6 children

James fredrick Durr
John francis Durr
Louis alfred Durr
emma Jane Durr
Thomas Durr
George Henry Durr

I Got the Slave Possibilty From Tim Rowan