A U.S. District Court judge has affirmed a magistrate judge's conclusion that two men charged with the 1975 slaying of a fellow American Indian Movement member can be tried together.

John Graham and Richard Marshall are to stand trial May 12 in Rapid City on charges they committed or aided and abetted the murder of Annie Mae Aquash near Wanblee.

The prosecution theory is that Marshall provided the gun Graham used to kill Aquash. Both men pleaded not guilty, and their lawyers asked for separate trials.

But U.S. Magistrate Judge Veronica Duffy issued an order in December concluding the law allows jurors to consider both men's cases together.

U.S. District Judge Lawrence Piersol affirmed that ruling in an order issued Thursday.