Chief Art Acevedo of the Houston Police Department said there were “material untruths or lies” in an affidavit for a search warrant that led to the raid, in which officers breached the door of a house in southeast Houston and a gunbattle broke out. Four officers were shot and two suspects were killed in the exchange.

“It’s a serious crime,” Acevedo said at a news conference Friday. “When we prepare a document to go into somebody’s home — there is a sanctity of somebody’s home — it has to be truthful.”

The revelation, which emerged from sealed affidavits that were obtained by local news outlets, cast a shadow over the department of 5,200 officers in the nation’s fourth-largest city. But Acevedo maintained that the police had reason to investigate the house, including a 911 call from a woman who said her daughter was there doing heroin.

“We have found no evidence that we were just there willy-nilly,” said Acevedo, who previously had said that officers found small amounts of cocaine and marijuana in the house.

An internal investigation found that narcotics officer Gerald Goines lied about using a confidential informant to buy heroin at the house that was under investigation, according to new affidavits posted by Channel 2, a Houston television station.

In his original search warrant affidavit, Goines said that on Jan. 27, he watched the informant go to the house, meet with a man inside and leave with “brown powder” that appeared to be heroin.

When a team of officers executed the search warrant Jan. 28, people inside the home began to shoot and the officers fired back, police said. Four officers were shot, including Goines, and a fifth officer sustained a knee injury.

Police identified two suspects, Dennis Tuttle, 59, and Rhogena Nicholas, 58, who died in the shootout.

Afterward, authorities said, officers visited Goines in the hospital and asked for the name of the confidential informant. On separate visits, he wrote down two different names, but when officers interviewed the informants, both said they had not worked with him on that case, according to the affidavits.

Police interviewed “all of the confidential informants” that had worked with Goines, the affidavits said, and “all denied making a buy” at that location.

Goines, who has been with the department for more than 30 years, and a second officer, who was mentioned in the original search affidavit, have been placed on administrative leave pending an investigation, Acevedo said Saturday.

Goines could not be reached for comment Saturday.

In a statement, the Houston Police Officers’ Union said the allegations were “extremely disturbing” and not reflective of the many Houston police officers who work hard every day.

“The officer at the center of this investigation, like any suspect in a criminal case, is innocent until proven guilty,” the union said. “However, at the end of the day, we are all law enforcement officers and the law must be equally enforced.”

Acevedo pledged to “leave no stone unturned” in the investigation, which he said would include looking into other cases Goines had worked on and auditing the narcotics department.

The shooting and the latest developments, he said, have angered other officers and left the victims’ families with “a lot of unanswered questions.”

“We owe it to them to get to the truth,” he said.

This article originally appeared in The New York Times.