Dante Moore, 27, turned himself in with his hands up and shirt off Wednesday afternoon. Activist Quanell X was by his side as he answered questions from the media.
"(Moore) was scared," Quanell X said.
Wednesday night, Moore was being held at the Houston city jail linked to the death of 52-year-old Bellaire motorcycle officer Marco Zarate. The murder charge was later finalized.
An image of Moore was captured by Zarate's body camera when he stopped two alleged shoplifters leaving Meyerland Plaza. Police believe the second person of interest is Moore's twin brother, Dominique Moore. The suspects drove off and during the ensuing chase Zarate lost control of his motorcycle and hit a landscaping trailer.
"The fact that he is cooperating, I don't know what that will mean for future prosecution," Bellaire Police Chief Byron Holloway said. "What it means to me is that he wants to resolve the issue and he is trying to do what he sees is the right thing."
Quanell X says Moore was scared and concerned about his safety.
"(Moore) kept saying to me, 'Are you sure they not going to shoot me?'," Quanell X said.
Moore has a prior criminal history that dates back to 2007 and a burglary charge, according to online court records. His last conviction was in 2013 for evading arrest from a Houston police officer. Records show he was recently released from prison. It's unclear whether his brother faces charges. The Houston Police Department is the investigating agency because the fatal crash happened within Houston city limits.
VIDEO: Community remembers Officer Anthony Marco Zarate
"I just think that it's important to stand behind our police officers. The officer was just doing his job and because of some senseless act, he lost his life," said Darlene Wilkens, who works in Bellaire.
Wilkens added flowers to the memorial to officer Marco Zarate. She did not know Zarate, but others stopping by the Bellaire Police Department did know the fallen Officer.
"He was one of our fellow employees, he worked with us. He was a great guy. He would do anything for anybody," M. Torres of Houston Mobility Response said. "Great husband, friend, co-worker, so we just paid our respects."
Zarate was active in Special Olympics Texas and participated in fundraisers like Tip a Cop and the Law Enforcement Torch Run.
He leaves behind a wife and three daughters. A fund for the family is being set up at Prosperity Bank.
Open visitation for Zarate will be held July 17, at Memorial Oaks, 13011 Katy Freeway from 12pm to 8pm. Funeral arrangements are still being finalized.
Visitation for Officer Marco Zarate on Sunday July 17th at Memorial Oaks 13011 Katy Fwy. 12:00 Noon to 8:00 PM – Open Visitation.— Bellaire Police TX (@bellairepd) July 13, 2016