Updated

The suspected killer of a Manhattan tech entrepreneur whose body was found dismembered last week has pleaded not guilty to second-degree murder, Fox News has learned.

Tyrese Haspil, 21, was the executive assistant to 33-year-old Fahim Saleh, the CEO of ride-hail company Gokada.

Police said Saleh’s cousin found Haspil dismembering Saleh’s body with an electric saw at his Lower East Side apartment before he escaped from the scene.

Tyrese Haspil, 21, being escorted out of the 7th precinct by NYPD detectives this past Friday.  (AP)

Prosecutors on Saturday said surveillance video showed Haspil buying the electric saw and cleaning supplies that were left near the body.

Haspil was arraigned just after midnight Saturday on a charge of second-degree murder in Saleh’s death. A spokesperson for Legal Aid Society, which is representing Haspil told Fox News he pleaded not guilty.

"We are in the very earliest stages of ferreting out the truth. The life of this case promises to be long and complex. As the attorneys for Mr. Haspil, we urge the public to keep an open mind," Legal Aid Society attorneys Sam Roberts and Neville Mitchell said in a prepared statement. They claimed there was "much more to this narrative" than the accusations and his arrest.

Investigators have recovered security video from Monday afternoon showing a man identified as Haspil following Saleh up the elevator to the full-floor, two-bedroom apartment, and shooting him with a stun gun, causing him to fall to the floor, according to the criminal complaint.

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The masked person following Saleh was dressed entirely in black, according to a law enforcement official who was briefed on the case but wasn't authorized to discuss the investigation and spoke on the condition of anonymity.

Video surveillance from a hardware store Tuesday morning showsed a man identified as Haspil purchasing the saw and cleaning supplies found at the seventh-floor apartment on the Lower East Side, according to the complaint.

This undated photo, provided by Gokada, shows company founder and CEO Fahim Saleh.  (Gokada via AP, File)

Officers responding to the cousin's 911 call discovered Saleh's clothed torso, bags containing a head and arms and an electric saw in the living room of his apartment on the Lower East Side, police said.

Saleh was stabbed five times in the neck and torso and had wounds on his arm and left hand. He was dismembered just below the knees, at both shoulders and the neck, according to court papers.

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Saleh's LinkedIn biography described him as a self-taught businessman who founded Gokada, building on his experience of first "seeing an opportunity in his parent's native country of Bangladesh" and starting that country's largest ride-sharing company. It said he also invested in a similar venture in Colombia.

The Associated Press contributed to this report.