Houston's police chief said Friday that there appear to be "some material untruths or lies" in an affidavit used to get a warrant for a drug raid that left four officers shot and two people in the home dead.

Police Chief Art Acevedo emphasized that police "had reason to investigate that location" on Harding Street, a raid that ended in a shootout that killed the two occupants, Dennis Tuttle, 59, and Rhogena Nicholas, 58.

"Thus far it appears that there are some material untruths or lies in that affidavit — and that's a problem," Acevedo said. "That's totally unacceptable."

"More than likely, the investigating officer will be charged with a serious crime at some point," the chief said.

He added that there will be a review of past investigations, as well as a broader look at the department’s narcotics unit street level units.

Earlier Friday, NBC affiliate KPRC of Houston obtained police documents that say narcotics Officer Gerald Goines justified the warrant request by claiming that he sent a confidential informant to make a narcotics buy at the home, and that the informant returned with what the informant said was heroin and said there was a weapon at the residence.

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But in the police documents, an investigator said they were unable to find that informant, and that all the informants listed as working with Goines denied making a drug buy for him at that home or ever buying from Tuttle or Nicholas. Acevedo acknowledged those documents Friday, but did not name the officer.

The police department has said that when officers were serving the felony warrant at the home at around 5 p.m. on Jan. 28, they were met with gunfire and several officers returned fire, killing Tuttle and Nicholas.

Police have said that a small amount of marijuana and white powder believed to be cocaine or fentanyl as well as three shotguns and two rifles were recovered after the raid on the home. Goines was one of the four officers wounded in the shooting, according to police documents.

"We're going to get to the truth," Acevedo said. He said the police department is conducting “an impartial investigation into everything that occurred leading up to and during that raid."

Houston Police Chief Art Acevedo talks to the media during a press conference at the police station in Houston on Feb. 15, 2019. Elizabeth Conley / Houston Chronicle via AP

Acevedo did not name what he called the "target officer" in the investigation into the shooting, but past cases will be investigated as well.

Acevedo said that one officer has previously been relieved of duty, and the person he referred to as the investigating officer is still hospitalized and will also be relieved. A message with the police union about whether Goines has legal representation was not immediately returned Friday night.

Acevedo said there was also a 911 call from a woman who said her daughter was doing heroin in the home that was raided. "This was not just an investigator deciding to go target a house, as far as we've determined so far, for no reason," he said.

If information was determined to have been falsified for the warrant it would be a crime, Acevedo said. But the details of exactly what occurred are still under investigation, he said. He said that search warrants have been obtained for cellphones.

"No matter what we end up with here, right, we know we have a criminal violation already — and a serious criminal violation by the individual that prepared that affidavit on the initial search warrant at the Harding Street location," Acevedo said.

The Houston Police Officers’ Union said in a statement to KPRC that the facts detailed by Acevedo on Friday were "extremely concerning."

"Such actions, if true, would be extremely disturbing and would not be a reflection of the many men and women of HPD who do an incredible job every day, including those who have worked tirelessly since the shooting ensuring that no stone goes unturned," the union said.

Acevedo pledged a thorough and impartial investigation.

"I"m telling you, there's a lot of pissed off cops right now," the police chief said. "There are a lot of angry cops. Because when you violate that oath of office, you make it hard for 98, 99 percent of these cops that go out there every day."