They simply had too many reasons to eliminate him. First of all, there was the matter of revenge for planting a propagator of disorder in their gang for the sole purpose of crippling their gang.
They have to pay him back for that. Even if they don't want to because of what they did to him, there is a second reason that compels them to seek to eliminate him.
This second reason is the matter of Cedric seeking revenge against them for setting him up with the propagator of justice. It is unlikely that Cedric will think what they did to him was fair, so it is likely that he will come after the again and this time, he will be more ruthless and desperate.
As it turned out, the second reason truly made Cedric a threat that they had to eliminate. This is because Cedric wanted revenge and he didn't leave Reinfield City like everyone thought he would.
He stuck around with plans to get back at the Golden Hammer gang and make the gang help him recover his innocence.
