Those beliefs were confirmed Tuesday around 11:10 a.m., when Pennsylvania State Police spotted Stephens' vehicle and attempted to pull him over. A brief auto chase ended in Stephens fatally shooting himself.
Earlier, Zuckerberg had said that Facebook was developing artificial intelligence to better flag content on the site.
"We are grateful that this has ended".
Stephens was the target of an intense manhunt in the Easter Sunday slaying of mechanic Robert Godwin.
In the Facebook video, which appears shaky, Stephens gets out of his auto and appears to randomly target Godwin, 74, who is holding a plastic shopping bag.
Police said it appeared Godwin was chosen at random.
State police gave chase and the suspect shot himself "as the vehicle was spinning out of control", police said.
Godwin's daughter, Tammy Godwin, told Lemon she learned of her father's death in a phone call from her mother.
Williams said the Cleveland police had received over 400 tips regarding Stephens' whereabouts. Stephens also broadcast a live video, in which he claimed to be responsible for numerous other murders.
Godwin is known to be Stephens' only victim, even though he wrote about killing 12 to 15 people. However, she said she still forgives him. "I am very sad for everyone involved".
Stephens, 37, shared a recording on Sunday of himself announcing his plan to kill someone, then two minutes later posted another video of himself shooting and killing Godwin, Facebook said.
Facebook posted a response to the incident on its blog Monday afternoon, penned by VP of Global Operations Justin Osofsky.
Before the start of Facebook's annual F8 developers conference, CEO Zuckerberg said: "We have a lot more to do here".