Prophet ‎﴾ﷺ﴿ Forgiving Murder
When after repenting and accepting Islam, even shirk can be forgiven, then it obviously makes sense to forgive lesser crimes than shirk if one repented sincerely. Many verses in the Qur’an, Allah says he forgives all sins except shirk.
Most likely because he repented and accepted Islam. His earlier crime was forgiven because of it.