Other forms: corroborating evidences
Corroborating evidence is a collection of facts and information that backs up someone's story. In a court of law, corroborating evidence is used to uphold the testimony of witnesses.
If you swear before a judge that you saw a suspect in front of a convenience store at a certain time, the store's security video might be corroborating evidence for your testimony. If you accuse your neighbor of denting the door of your car, a corresponding dent in her bumper could be corroborating evidence. Something that's corroborating confirms or gives legal support, and evidence is proof.