Cheyenne and Arapahoe tribal members are marking the 150th anniversary of the Sand Creek Massacre in Colorado, one of the deadliest massacres in American history.

They're paying tribute to two Army officers who refused to participate in the slaughter, which left about 200 Cheyenne and Arapaho dead. Many of those killed in the November 1864 massacre were women and children.

Capt. Silas Soule and Lt. Joseph Cramer were honored in a service early Wednesday at Denver's Riverside Cemetery. Tribal members are honoring their gravesites before completing an annual healing run to the state Capitol.

About 70 are running to the Capitol, where Gov. John Hickenlooper is expected to make an announcement about the massacre.

The four-day run began at the massacre site in Eads, about 180 miles southeast of Denver.