Saleh’s personal assistant, Tyrese Devon Haspil, 21, arrested on Friday, is expected to be charged in a criminal complaint with second-degree murder and other crimes, New York Times reported.

The Gokada CEO was discovered dead on Tuesday afternoon by his sister inside his $2.25 million condo in a luxury building on Manhattan’s Lower East Side, the police said.

Detectives believed that the motive for the killing stemmed from Mr Saleh having discovered that the assistant had stolen tens of thousands of dollars from him, despite the fact that Mr Saleh had not reported the man and had set up what amounted to a repayment plan for him to return the money, one of the officials said.

Saleh’s sister had gone to check in on him after not hearing from him for about a day. She found a gruesome scene that Saleh’s head and limbs had been removed, and parts of his body had been placed in large plastic bags. An electric saw was still plugged in nearby.

US investigators concluded that Saleh was killed on Monday, the day before his body was found and that the killer used his employer’s credit card to pay for a car to a Home Depot, on West 23rd Street in Manhattan, to buy cleaning supplies to sanitize the crime scene, the official said.

The killer returned to Saleh’s apartment the next day to dismember the body and clean up the crime scene.

Detectives believe that the killer, dressed in a black three-piece suit, wearing a black mask and carrying a duffel bag, followed Saleh off an elevator in his building and into his apartment, a law enforcement official said. He used a Taser to immobilize Saleh and then stabbed him to death.

Security video taken from inside the elevator shows the killer later using a battery-operated portable vacuum cleaner in an apparent effort to remove any traces of his presence, the official said.

New York City’s medical examiner announced on Thursday that Saleh had died from multiple stab wounds to his neck and torso. Initially, a law enforcement official had described the killing as a “hit” and said it looked “like a professional job.”

The killer’s work dismembering the body was interrupted when Saleh’s sister entered from the building’s lobby, another official said, prompting him to flee through the apartment’s back door and into a stairwell before the sister arrived.

Saleh’s family said in a statement on Wednesday that the gruesome killing was so shocking it was unfathomable.

“Fahim is more than what you are reading,” the family said. “He is so much more. His brilliant and innovative mind took everyone who was a part of his world on a journey and he made sure never to leave anyone behind.”

Gokada and the Nigerian tech community have since Saleh’s death poured in tributes to mourn the young entrepreneur.