OBITUARY Kool DJ AJ, Pioneering DJ for Kurtis Blow & Busy Bee, Dies: Hip-Hop Community Reacts

Kool DJ AJ -- a pioneering hip-hop DJ working since the late 1970s -- died Wednesday (Sept. 9), his friend and collaborator Kurtis Blow announced on Twitter.

AJ worked with Blow and Busy Bee throughout the '80s and DJ'd in to the '90s, retiring from hip-hop in 2010.

His exact age and cause of death are unknown.

The hip-hop community mourned the loss on social media with tribute posts. Check out the response below:

RIP to my DJ and friend Kool DJ AJ!!!! — Kurtis Blow (@KurtisBlow1) September 9, 2015

I put this Dj in front of my biggest crowds in the 70s and he never let me down Kool Dj AJ he was my… https://t.co/0TM4u9MPLp — Grandmaster Flash (@DJFlash4eva) September 9, 2015

Rip my friend Kool DJ AJ A photo posted by Kurtis Walker (@kurtisblow100) on Sep 9, 2015 at 1:17pm PDT

Rip to my friend Kool DJ AJ A photo posted by Kurtis Walker (@kurtisblow100) on Sep 9, 2015 at 8:21am PDT

R.I.P. To The Great Legend KOOL DJ AJ...Thanks For Teaching Us DJ's How To Keep The Skill Alive...#premierwuzhere A photo posted by @djpremier on Sep 9, 2015 at 11:24am PDT

RIP DJ AJ. Hip Hop Legend! https://t.co/DNk4gJfZeu — ICE T (@FINALLEVEL) September 9, 2015

RIP Kool DJ A.J. My condolences to your family, as well as Busy Bee & Kurtis Blow. UP IN THE BRONX WHERE THE PEOPLE ARE FRESH, THERE WAS ONE DJ WHO COULD PASS THE TEST. A photo posted by Big Daddy Kane (@officialbigdaddykane) on Sep 9, 2015 at 4:47pm PDT

DJ AJ a great pioneer in the rap game has passed away to today. Amazing sweet spirited human being. God accept him into greater service — Russell Simmons (@UncleRUSH) September 9, 2015

My condolences to the family of AJ Scratch. http://t.co/rvdemENNJx — TheRealPerceeP (@TheRealPerceeP) September 9, 2015

The legendary Kool DJ AJ has passed away - http://t.co/6MaIrN9FRk: http://t.co/WohLTcD3vQ — Chuck D (@MrChuckD) September 9, 2015

Kool Dj Aj Scratch..... Rest in peace... Love always... True pioneer.. One of the early super star DJs.... @ajproduction #KOOLDJAJ #AJScratch #DJAJ A photo posted by FunkFlex (@funkflex) on Sep 9, 2015 at 10:04am PDT