Scientists said on Monday that two patches of land in Tulsa, Okla., could be the sites of mass graves holding victims of a bloody 1921 clash in which white mobs attacked black residents and destroyed a prosperous business district known as Black Wall Street.

The evidence of possible mass graves, gathered by two archaeologists from the University of Oklahoma, is the latest discovery to spur more active interest in a brutal chapter that the city tried for decades largely to forget. It could lead to excavation of the sites, and possibly a memorial to the victims.

The massacre in Tulsa was one of the deadliest eruptions of race-motivated violence in the nation’s history. As many as 300 people were killed, and a whole section of the city destroyed, including more than 1,200 homes.

It began on May 31, 1921, after a black man was arrested and accused of sexually assaulting a white woman. (A state commission found in 2001 that it was more likely that the man had just accidentally stepped on the woman’s foot. The assault charges were later dropped.)

Tensions ran high, crowds gathered outside the courthouse and a local newspaper suggested that the man might be lynched, prompting some black residents to arm themselves and patrol the streets. A mob of white men then attacked and set fire to the predominantly black Greenwood neighborhood, including the business district known as Black Wall Street.