A recently surfaced tip scrawled on a yellow legal pad that a southeast patrol officer passed to a narcotics lieutenant she was romantically involved with apparently triggered the botched drug raid that resulted in murder charges against a Houston police officer, according to probable cause affidavits.

Former HPD officer Gerald Goines, 54, faces two felony murder counts in the January deaths of homeowners Rhogena “Reggie” Nicholas and Dennis Tuttle. His partner, Steven Bryant, has been charged with tampering with a government document. Both men turned themselves in late Friday and were later released on bail.

While the department has divulged some aspects of what led up to the raid, the new documents provide the most detailed explanation so far about how a seemingly mundane patrol call led to a deadly confrontation. Serious questions about the department protocol used to defend the no-knock raid remain, particularly in regards to the informal nature that the complaint was logged and circulated.

“The only justification that the police keep clinging to is, ‘We really did have probable cause,’” said Mike Doyle, an attorney representing family members of Nicholas and Tuttle. “That’s apparently the only thing they have to stop them from owning up to that they never should have been there.”

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The home first came under scrutiny after a Jan. 8 call to police from an anonymous woman who said her daughter was using drugs in the house with a woman named “Reggie,” according to the court documents filed Friday.

The caller told police that she’d seen multiple guns in the home and that the people inside would not cooperate with law enforcement.

Nicole Blankinship-Reeves and her partner, Officer R. Morales, visited the house but did not find an indication of criminal activity, the records show, but contacted the original tipster, the caller insisted officers enter the home.

Blankinship-Reeves continued to research the home but didn’t take any further action that day, according to the court documents. Instead, she jotted her notes down on a yellow legal pad and turned it over to her girlfriend, Marsha Todd, a lieutenant who oversees the narcotics division’s FAST squad, which handles the division’s civil asset forfeiture cases. Three days later, Todd relayed the tip to Goines, who worked on a different squad in the same division. On Jan. 28, Goines sought a no-knock warrant from a municipal court judge. Several hours later, he and 10 other narcotics officers raided the Harding Street home.

READ MORE: A botched drug raid led to a wave of leaks. Cops peeking at internal records then found themselves under investigation.

The department’s Harding Street bust went awry almost immediately after narcotics officers burst into the home, shooting a dog they say lunged at them and sparking a gun battle.

As police probed the incident in the days that followed, investigators realized they couldn’t verify Goines’ claims about the drug buy he’d used as the basis for the raid and that he may have fabricated information used in a sworn affidavit he used to obtain the warrant he used to raid the home.

Chief Art Acevedo maintains that his officers were on solid ground to investigate the home even while condemning Goines and Bryant for “dishonoring the badge.”

He said Saturday that officers frequently share intelligence with each other.

“It’s not uncommon for patrol officers to provide information to specialized units,” he said. “However, as information flows up and down the chain of command, my expectation will be that in the future, supervisors and managers from respective units are kept in the loop.”

Houston Police Officers’ Union Vice President Doug Griffith said it was “common practice” for street officers to pass information about drug activity to narcotics officers to investigate.

“It happens all the time,” he said.

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To Nicole DeBorde, the attorney representing Goines, the information in the court documents didn’t raise any red flags.

“The details support that it was a legitimate investigation based on a tip from a person living in that community that drugs were being sold from that location,” she said. “It is the narcotics division that is tasked with investigating these tips from members in the community who want to stop drug-dealing in their neighborhoods.”

But Doyle, the attorney representing the Nicholas family, questioned the reliability of the new information.

“When did the legal pad story appear?” he said. “Does anybody really know when it was written?”

The story as to why police zeroed in on the home has evolved over time, he said. The original call sheet from Jan. 8 was blank, he said, arguing that affidavit used to get the no-knock warrant now appears to have been based on false information.

To Scott Henson, a criminal justice expert and the executive director of the nonprofit Just Liberty, the new information outlined in the probable cause statement didn’t necessarily raise concerns — though it did raise questions about what was on the yellow legal pad and why that would prompt Goines to potentially fabricate an interaction with an informant.

“You really want to know what’s on that piece of paper that makes (Goines) think that level of urgency was necessary,” he said. “My suspicion is that if he felt like he had to make up an informant, there must not be much incriminating on that legal pad.”

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Police veterans and independent experts were split over whether informal tips like this should raise concerns.

But Larry Karson, an assistant professor of criminal justice at the University of Houston-Downtown, said the court documents’ information reflected standard policework.

“It’s not unusual at the beginning of an investigation, because not everything will necessarily pan out,” he said. “As they develop the case, more of a documentary trail will appear to help establish probable cause, but before that happens, people are simply trying to determine if it’s worth the energy.”

The documents show a failure to follow department safeguards to properly vet information and conduct thorough investigations, said one HPD supervisor who asked not to be identified in order to speak freely.

“We have procedures in place that dictate how things are done,” the supervisor said. “You can’t just make off the cuff comments and launch an investigation. There’s a reason we have supervisors — to vet this stuff. They’re the decision makers.”

Roger Clark, a former narcotics lieutenant with the Los Angeles County Sheriff’s Department, said while informal tips can lead to investigations, the situation in the Harding Street raid raised serious questions about HPD’s policies on passing information from one command to another.

“What you’ve got is stationhouse gossip, and from that an officer fabricated a warrant which turns to be really bad and led in death,” he said. “Had officers followed the normal procedure here, it may have prevented this from developing the way it did.”

Sam Walker, an expert on police procedure at the University of Nebraska at Omaha, said the information in the documents point to potentially serious problems about vetting information and lack of control for officers who routinely engage in dangerous operations.

“It begins to move into gossip and second-hand information,” he said. “That’s the reason for good chain of command procedures.”

Nearly seven months after the failed raid, the ramifications of the operation continue to unfurl: The FBI launched a civil rights investigation into the incident, while District Attorney Kim Ogg announced prosecutors were reviewing more than 2,000 cases previously handled by Goines and Bryant and dismissed dozens of the two officers’ active cases.

And internal police records show that as rumors inside HPD swirled, dozens of officers came under investigation for looking up Todd and Blankinship-Reeves’ personal information on an internal HPD personnel database.

The investigation, which came several weeks after the Jan. 28 raid, scrutinized 37 officers and civilian employees. Months later, 17 people were disciplined with so-called “supervisory interventions,” a warning that is less severe than a written reprimand, the Chronicle previously reported.

Then in late July, a federal grand jury began subpoenaing HPD officers as it began probing the shooting. Blankinship-Reeves and Todd were among the first officers to appear.