Veteran Brooklyn, New York MC Pumpkinhead (a/k/a PH) has been reported dead this morning (June 9). Friends and collaborators of the man born Robert Alan Diaz have begun to publicly mourn. Notably, Pumpkinhead appeared on acclaimed albums such as Immortal Technique’s Revolutionary 1 and Revolutionary 2 albums, in addition to Jean Grae’s Bootleg Of A Bootleg EP.

A onetime protege of Bobbito (of Stretch Armstrong & Bobbito), Pumpkinhead would first find success in the underground Hip-Hop community in the late 1990s. His 12″ single “Dynamic” was popular on both coasts, making a name for the MC who shared his name with the Horror film.

In 2001, Diaz released The Old Testament on Makin’ Records. A label-mate of Grae and The Juggaknots, he would follow-up in 2003 on Third Earth with Beautiful Mind. However, it was the mid-2000s that Pumpkinhead released what many Heads considered to be his best work. 2005’s Orange Moon Over Brooklyn, produced entirely by Marco Polo, would gain the attention of Soulspazm/Rawkus Records. Along with Marco, Kidz In The Hall and Mr. J. Medeiros, P.H. was among the final wave of releases at Rawkus—the label responsible for mass-introducing Mos Def, Company Flow, and Talib Kweli.

In the decade since, Pumpkinhead released 2008’s Picture This project, featuring Murs, Del The Funky Homosapien, Royce Da 5’9″ and Kweli. The Brooklyn Academy member would also drop 2011’s Know The Ledge. In recent years, the lyricist would gain recognition through the Battle Rap circuit, having honed his skills through freestyles and cyphers.

The cause of Robert Diaz’s death has not been made public.

Talib Kweli, who had known Diaz since the age of 10, was among those to mourn today:

Just finding out I lost a great friend today. RIP Robert Diaz AKA Pumpkinhead. Robert and I went to PS 282 together in Brooklyn, 4th grade. We then reconnected when he became an MC during the indie era of the late 90s. He signed to Makin Records, I signed to Rawkus. Then PH went on to reinvent himself again in the new battle rap era. He LOVED MCing and was great at it. To lose such a great human being so early in his life, man. No words. There is a fraternity of artists who were around for all of this. PH inspired us all. He will live on thru us even though his physical presence will be missed. RIP Robert Diaz.

A photo posted by Talib Kweli (@talibkweli) on Jun 9, 2015 at 9:51am PDT

Immortal Technique also seemingly spoke (via Twitter) on his early collaborator:

I don’t want to believe this is true, but it is. I hate hearing things like this about anybody. Much less about the people you love. — IG: TechImmortal (@ImmortalTech) June 9, 2015

Marco

Today is a very shitty day. Just got word my brother Pumpkinhead passed away at 5:40am this morning. My condolences to his family…R.I.P.

— Marco Polo (@marcopolobeats) June 9, 2015

One of the first people to give me a shot when I moved to New York and I’m honored to have recorded “Orange Moon Over Brooklyn” with you. — Marco Polo (@marcopolobeats) June 9, 2015

Ambrosia For Heads extends condolences to the family, friends, and fans of Pumpkinhead. Rest in peace.

Related: Listen to the Best Hip-Hop of May 2015 in One Playlist (Audio)