An Arizona man killed himself and his entire family when he deliberately drove into a lake after meeting with his estranged wife and three young children to talk about the kids, officials said.

Surveillance footage captured the final moments of the family of five. Video allegedly shows Glenn Baxter, 27, driving his SUV to Tempe Town Lake before speeding toward the body of water with his wife, Danica Baxter, 25, and their three children— all under four years old— inside at about 12:15 p.m. on Sunday.

Investigators have labeled the incident a murder-suicide, Tempe Police said.

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"You're gonna see him back the vehicle up and drive it at a high rate of speed towards the lake down the sidewalk, making an abrupt left turn towards the lake," said Lt. Mike Pooley with Tempe Police, who described the video to reporters at a press conference and said that Glenn Baxter got out of his SUV and walked to the lake before he drove into the water.

Danica's aunt, Tamika Franklin, watched the surveillance footage for clues of what happened and told INSIDE EDITION she did not believe Danica was conscious when her estranged husband aimed for the lake.

"I'm trying to figure out how he parked the truck and was walking along the lake and there was no movement at the car," Franklin said to IE. "I'm thinking my niece was unconscious already. I just can't see my niece not trying to get out of there."

Two witnesses dove into the lake to follow Baxter's silver Nissan Armada and pulled out Danica from the SUV, which had flipped over before landing in the water, Pooley said.

Police also jumped into the water and pulled out little Zariyah, 1, her big brother Nazyiah, 2, and Glenn Baxter, but all died at a local hospital, Pooley said.

A few hours later, investigators discovered that the couple was separated and their oldest child, 3-year-old Reighn, was unaccounted for.

"We didn’t know where he was," Pooley said. "Our worst fear was he was in this vehicle... and our worst fears came true. He was located in the very backseat, in the third seat, he was strapped in his car seat and he was still wearing his pajamas."

His body was pulled from the submerged SUV about 10 a.m., police said.

Police said a handgun was also recovered from the SUV, but no one in the car had been shot.

"This was not an accident. Mr. Baxter took deliberate action," Pooley said. "We're talking these little kids, they (are) completely innocent, completely helpless in a situation like this, and it is absolutely horrific what happened to these little kids and their mother."

Danica’s final text messages discussed dropping off the children with her mother-in-law, Pooley said.

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Though they were separated and no longer living together, the Baxters met Sunday night to discuss the children, Pooley said.

"(The video footage shows) no attempt for Danica to get out, the children, you don’t see them in the video... What happened inside that vehicle remains a mystery," Pooley said. “It’s one of those deals, you’re going to think about it for a while. You’re going to go home and just be glad to be with your family.”

Devastated family members took to the fundraising site GoFundMe to write about the young mother and her three children, appealing to the masses to help offset costs for the four funerals ahead.

"She was a strong independent woman who never complained about anything that was handed her way! We would like to send her and her babies off in the best way possible," family wrote.

In one day, nearly $2,000 had been raised, as mourners posted comments with their donations.

"What a senseless waste of life, I'm so sorry for your loss, my heart truly goes out to you," one woman from the United Kingdom wrote.

"My heart breaks for the mother and those 3 beautiful babies and for the family left behind that's suffering such a tragic loss and so many questions left unanswered," another woman wrote.

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