Republican presidential candidate Donald Trump on Sunday chose not to distance himself from the Ku Klux Klan and former KKK Grand Dragon David Duke because he said that he wanted to “do research” on the groups supporting him.

Last week, the Anti-Defamation League called on Trump to slam white supremacist groups and “publicly condemn their racism” after Duke endorsed him, saying that white people who did not vote for Trump had committed “treason to your heritage.”

On Sunday, CNN’s Jake Tapper asked Trump if he wanted David Duke’s vote “or that of other white supremacists.”

“I don’t know anything about David Duke,” Trump insisted. “I don’t know anything about what you are even talking about with white supremacy or white supremacists. So, I don’t know. I mean, did he endorse me or what’s going on?”

“Because I know nothing about David Duke, I know nothing about white supremacists,” he added. “And so, you are asking me a question that I’m supposed to be talking about people that I know nothing about.”

Watch the video below from CNN’s State of the Union, broadcast Feb. 28, 2016.