Saleh's former executive assistant, Tyrese Haspil, 21, was arrested Friday and hit with second-degree murder charges, the NYPD said.
Police said Haspil used a Taser to immobilize Saleh before stabbing him to death. Saleh's head, arms and legs had been severed.
Saleh co-founded Pathao, a ride-share app that's popular in Bangladesh. More recently, he was the CEO of Gokada, a motorcycle ride-sharing and delivery company based in Nigeria, which has faced financial setbacks and recently laid off most of its staff.
The motive for the murder appeared to be a dispute over money.
NYPD Chief of Detectives Rodney Harrison said that Haspil owed Saleh a "significant amount of money." Police sources put the amount in excess of $100,000.
Detectives also recovered text messages between the two that indicated Saleh accused Haspil of stealing the money, sources said.
The sources also said that Haspil was tracked using his credit card, which is believed to have been paid for by Saleh. The credit card was used to purchase the electric saw discovered in the victim’s apartment and was also used to pay for the suspect's rides to and from the location. Finally, the same credit card was used to pay for a car service to Home Depot where the suspect bought cleaning supplies, sources said.
It was not immediately clear if Haspil had obtained an attorney.
Saleh's body was found Tuesday afternoon by his cousin, according to police.
"The headlines talk about a crime we still cannot fathom," Saleh's family said in a statement earlier this week. "Fahim is more than what you are reading. 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. Fahim found success at an early age and built on it year after year, while remaining grounded and committed to helping others."
"No matter what he did, he did it while thinking of the greater good and his family," the statement continued. "His parents and his sisters were his light and he was theirs. There are no words or actions to provide any of us comfort except the capture of the person who exhibited nothing short of evil upon our loved one."