Police have arrested two additional suspects in relation to a robbery that happened last month in St. Catharines. The incident saw a victim attacked at an apartment building on St. Paul street. 3 suspects engaged in a violent altercation resulting in the victim suffering from severe injuries of multiple stab wounds to his back and face. Police say a 36 year old man turned himself in on Thursday, while another was charged with robbery. The final suspect was already in custody for another matter.