Tech C.E.O., Fahim Saleh’s body parts were found on July 14 inside plastic garbage bags in his Manhattan apartment located on the Lower East Side. In a public briefing on Wednesday, investigators revealed that Saleh’s killer, dressed entirely in black and wearing a black mask, followed the tech entrepreneur from the elevator of his luxury building, into his apartment.

Detectives believe the killer then used an electrical stun gun to immobilize Saleh, before decapitating the entrepreneur and dismembering his body with an electric saw. Saleh was 33 at the time of his killing.

Police are conducting an extensive investigation both inside and outside of Saleh’s condo. After reviewing surveillance videos and interviewing the entrepreneur’s sister, investigators believe the killer’s dismemberment of Saleh’s body was interrupted when his sister entered the apartment to check on him after not hearing from Saleh for a day.

Detectives believe the killer escaped through the apartment’s back door and down the building’s stairwell when she arrived.

The electric saw believed to have been used by Saleh’s killer was still plugged into an electrical outlet when the police arrived at the scene. It also appeared that the killer had made some effort to clean up the evidence.

During the Wednesday briefing, the official stated the killing “looks like a professional job” and referred to it as a “hit.” For now, detectives are keeping much evidence to themselves as the investigation into Saleh’s killing is fresh and ongoing.

A spokesperson from Saleh’s luxury building’s management company stated that Saleh was an active member of the condominium board and “the unit owners, residents, board and management are all quite upset.”

Saleh was the son of Bangladeshi immigrants. He was known for founding ride-hailing companies in Bangladesh and Nigeria along with a Manhattan-based venture-capital fund that largely invested in companies in the developing world.