21 more unmarked graves are discovered in the Tulsa Race Massacre investigation

Scientists at the site in Tulsa, Okla., will begin excavating by hand, using finer grain tools to clean up the coffins. That will help researchers analyze the construction style and hardware of the caskets in order to determine when they were interred. (City of Tulsa)

Researchers have unearthed an additional 21 unmarked adult graves that could be linked to victims of the 1921 Tulsa Race Massacre.

Tulsa, Okla., city officials announced on Monday that 17 adult-sized graves were uncovered at an excavation site in the Oaklawn Cemetery and another four were found on Tuesday, including two child-sized burials.