Very intriguing question. This case (below) seems to show that for a co-defendant to testify favorably for another co-defendant, they have to be severed from the case and have a separate trial.
: Whether the trial court erred in denying Mr. Rollerson’s motion to sever his trial from Ms. Burns’s trial in order to be able to call her as a witness to testify he was not involved in the Elvans Road Incident?
: Yes. While a trial court has discretion whether to grant a motion to sever, a court must grant such a motion if a defendant can show there will be “manifest prejudice” from being tried jointly. Under Jackson v. United States
, 329 A.2d 782 (D.C. 1974), when a defendant wants to sever a trial from a co-defendant in order to have that person testify in his defense, the court should grant the motion if it has been established that the co-defendant is 1) likely to testify and 2) the testimony will be “substantially exculpatory.”
A Court Should Grant A Motion To Sever If A Co-Defendant Would Provide “Officially Exculpatory” Testimony
Exculpatory evidence is evidence favorable to the defendant in a criminal trial that exonerates or tends to exonerate the defendant of guilt. It is the opposite of inculpatory evidence, which tends to prove guilt.
The Wagner's are not co-defendants ( I think but can't know for sure) because they are all having separate trials.
It's my understanding that any one of them could testify for the other. But we should get a Websleuth Attorney on here to see what they think about the Wags testifying FAVORABLY for each other at each other's trials.
......I'm not an attorney and am only giving my impressions and opinions.....