Shooter's 7.14.2020 FB repost was from a 7.13.2020 meme by Muslim Hub. Muslim Hub wrote: "Advice of the Prophet (pbuh) during his farewell sermon." The meme image content was: "O PEOPLE, LISTEN TO ME IN EARNEST, WORSHIP ALLAH, SAY YOUR FIVE DAILY PRAYERS [SALAH], FAST DURING THE MONTH OF RAMADAN, AND GIVE YOUR WEALTH IN ZAKAT, PERFORM HAJJ IF YOU CAN AFFORD TO. THE LAST SERMON OF PROPHET MUHAMMAD." At the bottom was a green diamond image - within that it reads "muslim AND PROUD" and below that also within diamond in smaller type: "Learn, Believe, Inspire"
Info based upon firsthand screen shot I took of his FB page over two hours ago. FB deleted the page (or access to it) around 8:24 Pacific time; 9:24 Mountain Time. (All within an hour of Boulder Police press conference which id'd him)
If you took a screenshot of slime's FB, rather than describe it, you could, hm, I don't know, POST IT? Like this one...