[3] He became involved in the resistance to slavery in 1843 when he was among a crowd of people who intimidated some bounty hunters who were returning an escaped slave to his owners.
Mitchell later reported that the man, who had a wife and children, had been given away by the local white pastor who claimed a $100 bounty.
[4] Mitchell's book garnered recommendations from leading abolitionists including the American activist William Howard Day and the British politician George Thompson.
The two of them both wrote books and they went on lecture tours of anti-slavery groups in Ireland, Scotland and England (all then part of the United Kingdom) and gathered funds for their churches in Canada.
[6] Despite the death of his daughter, Mitchell traveled again to Great Britain in 1863 to 1864 when a controversy erupted over his poor accounting and the potential mixing of his expenses with the hundreds of pounds (sterling) that he was meant to be sending back to Canada.