How do i finish my story?

If Burns used to be a criminal, make it so that the gang in question is the one he used to run with. He could be hiding his tattoos and you could have another detective character find out. You could also make it so the victim is the son of an old gang buddy and Burns ends up helping the gang find out who commit ed the murder while still trying to maintain his career as a detective. You could make the other detective who finds Burn's tattoo a rival of Burns, so they would have some sort of struggle.