The actor, best known for roles on Surface and Devious Maids, died Sunday, November 1 at the age of 30.
According to NBC News, Hassell was shot dead.
Police in Grand Prairie, Texas, explained that they responded to a shooting at 1:50 a.m. on Sunday, where they found Hassell, of Waco, “suffering from apparent gunshot wounds.”
The actor's manager said he was shot in the stomach.
Officers gave first aid to Hassell, but he passed away after being transported to a hospital.
Hassell was shot outside his girlfriend's apartment, and, according to reports, she did not see the assailant.
The investigation is ongoing, and no other details were made available.
Hassell was born on July 16, 1990 in Corsicana, Texas.
On the small screen, he starred on Surface alongside Lake Bell and Leighton Meester.
Hassell also made appearances on television shows such as Aaron Sorkin’s Studio 60 on the Sunset Strip,