Although 33 years passed before Richard "Dickie" Marshall was charged in the 1975 slaying of American Indian Movement activist Annie Mae Aquash, the case against him should proceed, federal prosecutors said in a motion filed Dec. 31 in U.S. District Court.

Marshall, 57, is scheduled to go to trial next month along with co-defendant John Graham. Both are charged with first-degree murder and face life in prison if convicted.

Marshall's attorney, Dana Hanna, filed a motion in December asking that charges against his client be dismissed, saying the government has an unfair advantage because it took so long to charge Marshall.

Hanna said several potential defense witnesses have since died.

But prosecutors argued in their motion that Hanna has not proven that any information those witnesses might have provided is not available through other sources.

They also noted that defense attorneys have the opportunity to question a cooperating witness, who says Marshall and Theda Clarke made incriminating statements to him. Defense attorneys can also subpoena Arlo Looking Cloud, who was convicted in Aquash's murder in 2004 and is serving a life sentence.

According to the government's motion, Marshall also would have to - but did not - prove the government delayed his indictment in order to harass him or gain a tactical advantage.

"For important and obvious reasons, prosecutors are under no duty to file charges as soon as probable cause exists but before they are satisfied they will be able to establish a suspect's guilt beyond a reasonable doubt," prosecutors stated. They said any delay was "appropriately investigative."

There is no limitation on when prosecutors can accuse someone of murder.