No it was not, if it was founded by the Democratic Party, the Democratic Party would have been sued out of existence ages ago.
The KKK, segregation, and slavery were Southern, not Democratic Party. That's why all those were restricted to the South. Well there used to be slavery up North as well, but far less and it ended far sooner, sans war. You know what else was up north as well? Democrats. And again that stuff does not apply up north. My parents were Democrats at a time that it was legal to lynch them to death in the South. I'm pretty sure that they didn't get lynched nor had anything to do with lynching or endorsing lynching.
No, that was not a recent report you saw from the FBI. You saw that he had anti-fascist inscriptions on some casings. Not all anti-fascist anything is automatically Antifa.
You said, "his bullet casings were engraved with pro-trans and ANTIFA stuff."
You have not substantiated any of that.