Man charged for selling drugs in deadly Cobb County overdose

marietta - Marietta police say a fentanyl dealer has been charged with felony manslaughter, almost a year after the alleged crime.

What we know:

Marietta police were called to an apartment complex on Powder Springs Street last September where they found 27-year-old Tyler Hass who had overdosed. He was pronounced deceased. 

Over the past year, Marietta Police investigators worked closely with the DEA, GBI, the medical examiner and the district attorney's office to find out  where Hass got the deadly drug.

Investigators searched the apartment and found a powdery substance and Hass' phone.  Investigators say that phone contained key information.  

Agents with the DEA did a digital extraction of the cell phone. An analysis of the information revealed Snapchat messages arranging a drug transaction, including a price to be paid by Zelle in exchange for fentanyl.

Investigators determined that the conversation was between Hass and Grant Mull.

In July, the GBI confirmed the powdery substance was fentanyl.

"That fentanyl was almost 100% pure," said Marietta Police Officer Chuck McPhilamy.

A short time later Mull was arrested and charged with aggravated involuntary manslaughter for fentanyl overdose death.

What they're saying:

McPhilamy says it took multiple agencies working together to get Mull off the streets.

"If it weren't for the efforts of all of these agencies working together, this suspect would still be at large in our community, dealing drugs and profiting off the pain and potentially death of others," said McPhilamy.

Marietta police say this is likely the first time in Cobb County that someone accused of selling drugs is facing manslaughter charges.