NORMAN, Okla. — As the University of Oklahoma expelled two students Tuesday for leading a racist song that sparked outrage across the country, the fraternity involved said it would investigate incidents at other campuses as it faced questions over the chant’s use by members at other universities.

Former members of the fraternity, Sigma Alpha Epsilon, claimed on social media that the same chant was used at colleges in other states, and University of Oklahoma officials investigating the episode said they did not believe the song had originated on their campus.

“I’m not sure that it’s strictly local,” said the university’s president, David L. Boren, a former Oklahoma governor and United States senator. Mr. Boren expelled the two students Tuesday but did not identify them, saying they had played a leading a role in the singing of the chant and “created a hostile learning environment for others.”

The fraternity’s national headquarters said the song was not a part of the “Sigma Alpha Epsilon tradition.”