Mac Miller Death Investigation Triggers Third Alleged Dealer Arrest

The investigation into who gave Mac Miller a deadly dose of pills has resulted in the arrest of a third person.

Law enforcement sources tell Stephen "Stevie" Walter was arrested Monday in Los Angeles. According to docs, Walter was contacted by Cameron James Pettit on the night of September 4, 2018 Mac died on Sept. 7 asking for "10 blues" Percocet pills.

Cops say Mac had texted Pettit the following

Mac -- "percs?"

Pettit -- "I got some dilaudid 2s but that's about it. I could get yellows and blues though"

Mac -- "blues as far as percs?"

Pettit -- "Yeah 30s"

Mac -- "Those are my sh*tttts man"

From there, according to cops, Pettit then contacted Walter to obtain the ten blues. Walter sent a runner to Pettit with the pills -- and Pettit delivered them to Mac at about 2:30 AM on September 5 -- the rapper was found dead on September 7.

The runner was allegedly Ryan Reavis who was arrested earlier this week in Lake Havasu in connection to Mac's death.

During their investigation of Mac's death scene, cops found a magazine in his bedroom covered with blue-colored powder and indentations near a rolled piece of paper and a gift card. 

Cops say the scene indicated Mac crushed or snorted one or more pills ... only 6 of the 10 pills were recovered.