Is it true that Dylan was the one who told Brooks Brown that he was on Eric’s hit list?

I was reading about Columbine, and the article said that Dylan was the one who told Brooks Brown that he was on Eric’s list on his website. Is this true? If so, why did Dylan tell, but turn around and commit one of the worst mass shootings with him? It doesn’t make any sense to me why Dylan would warn someone about being on a hit list. But then commit murder himself.