It's all over Google from court reporters from all media, he said it
https://www.washingtonpost.com/nation/2021/11/05/ahmaud-arbery-trial-opening-arguments/

“Stop, I’ll blow your f---ing head off,” Greg McMichael told police he warned Arbery


EDIT: Google help
https://www.google.com/search?q=McMichael+told+ahmaud+arbery+%22ill+blow+your+head+off%22&client=firefox-b-1-d&ei=ILaeYerALLawytMPx9650A4&ved=0ahUKEwjq0LP0_7H0AhU2mHIEHUdvDuoQ4dUDCA0&oq=McMichael+told+ahmaud+arbery+%22ill+blow+your+head+off%22&gs_lcp=Cgdnd3Mtd2l6EAw6BwgAELADEEM6BwgAELADEB46BQgAEIAEOgYIABAHEB46CggAELEDEIMBEAo6BQgAEM0CSgQIQRgBUKkKWMPQAWDF7QFoAXAAeACAAaoBiAG5IpIBBDIuMzWYAQCgAQGgAQLIAQLAAQE&sclient=gws-wiz

Last edited by Bwana_1; 11/24/21.