WOODLAND, Calif. — Testimony in the retrial of Carlos Reales Dominguez resumed Wednesday in Yolo County Superior Court, where prosecutors presented testimony from a former roommate, a neighboring resident and an Amazon employee in an effort to establish changes in Dominguez’s behavior before the 2023 Davis stabbings and examine digital evidence tied to an online account. The day’s testimony focused on eyewitness observations, Dominguez’s interactions with others and Amazon search and purchase records introduced by the prosecution.
Dominguez is charged with two counts of second-degree murder in the fatal stabbings of David Breaux and Karim Abou Najm, as well as one count of attempted murder for the stabbing of Kimberlee Guillory, who survived after suffering critical injuries during the 2023 attacks. He is also charged with enhancements for the use of a deadly weapon and circumstances in aggravation.
The prosecution first recalled a former roommate, fraternity brother and friend of Dominguez, who testified that he was a former University of California, Davis, student majoring in psychology. He said he first met Dominguez when he was a third-year student and Dominguez was a freshman going through the fraternity rush process.
When questioned by Deputy District Attorney Matt De Moura about Dominguez’s everyday behavior, the witness testified he had seen Dominguez “laughing, joke around, and show emotion.” He stated that, other than being quiet, he never noticed anything unusual about Dominguez during his first year at UC Davis.
“There were times the two of us would hang out … I enjoyed hanging out with him,” the witness told the court.
De Moura then directed the witness’s attention to the latter part of Dominguez’s freshman year and asked whether Dominguez had ever asked him if he “heard voices.”
“Yes,” the witness testified. However, he said he could not recall exactly when the conversation occurred and was instructed by De Moura to review testimony from the previous trial on May 20, 2025.
After reviewing the transcript, De Moura asked, “Does this refresh your memory from when this conversation took place?”
The witness responded, “Towards the end of the school year.”
The witness testified that after Dominguez asked whether he had ever heard voices, he asked Dominguez the same question in return.
“I asked him if he wanted to talk to somebody about it,” the witness told the court, “but the conversation did not go beyond that.”
When De Moura asked whether he ever followed up with Dominguez about the conversation, the witness replied, “No.”
According to the witness, Dominguez moved into the witness’s residence on Hawthorn Lane during the summer of 2022, before his sophomore year.
“When he had first moved in, I noticed that he had lost weight and that his hair was longer,” the witness testified.
The witness also recalled another occasion after Dominguez moved into the residence when Dominguez asked whether he could hear people talking.
“I could not hear people talking,” the witness told the court.
When asked whether he noticed changes in Dominguez compared with when they first met, the witness testified that he observed a significant difference in the way Dominguez walked.
“He would walk with his arms barely moving at his sides,” the witness said. “They would not swing in a normal manner.”
The witness added that Dominguez stared about a yard ahead of himself toward the ground.
“He kept his feet low with minimal movement … This was unusual to me. I had never seen him walk this way before,” the witness testified.
Asked whether he attempted to engage Dominguez while they lived together, the witness said he frequently tried to start conversations but usually received little response.
“Most of the time he would ignore me completely. He would do the same with our other roommates,” he testified.
The witness also described an altercation during a house party in the fall of 2022.
“That was the first time, other than joking around, that Carlos had ever pushed me,” the witness told the court. “He attempted to take a swing at me, but missed and I was able to restrain him.”
The witness testified that Dominguez simply left after the confrontation and described the encounter as “a confusing experience.”
“I had no idea why my friend was pushing and swinging at me,” the witness stated.
The prosecution also presented the testimony of neighbor and musician Mr. Hahn, who recalled seeing Dominguez return home around 3 a.m. during the spring of 2023. Hahn testified that the image of Dominguez’s “smile” or “smirk” remained memorable.
When prosecutors asked whether that detail still stood out in his memory, Hahn answered, “Yes.”
Prosecutors questioned Hahn about his work schedule during April and May 2023.
Hahn testified that he typically worked evening shifts at the G St. WunderBar from about 5 p.m. until closing, usually Wednesday through Friday. Because he walked home after work, he said he could estimate when he saw Dominguez returning home.
Hahn testified that after work he often sat on his patio to smoke, have a drink and “try to decompress from work.”
He recalled seeing Dominguez return home around 3 a.m., which caught his attention because of the late hour.
When prosecutors asked whether anything besides the smile stood out that night, Hahn testified that Dominguez “was out at three in the morning” before going inside without speaking.
After additional questioning, Hahn testified that Dominguez appeared calm initially but “picked up his pace a little bit” after noticing Hahn outside.
Defense attorney Daniel Hutchinson objected several times, arguing Hahn was speculating, and portions of the testimony were stricken by the judge.
During cross-examination, Hutchinson questioned why Hahn had never mentioned Dominguez speeding up during previous interviews or testimony.
Hahn responded that “it just wasn’t asked or brought up.”
He also testified that he believed he discussed the incident the following morning with individuals named Mark and Sid and thought he mentioned it to a responding police officer.
The prosecution next called John Franklin Blackmer, a business intelligence engineer at Amazon, who testified about Amazon’s customer data systems.
Blackmer explained that Amazon stores customer information, including search history, shopping history, order history and click activity, while maintaining separate classifications for customer and product information.
Blackmer testified that Amazon records both the exact words customers type into the search bar and any suggested searches selected by users.
He also explained that timestamps are stored in Coordinated Universal Time and must be converted to Pacific Time. Records also contain session identifiers tied to specific devices but do not identify whether activity occurred on a phone, tablet or computer.
Prosecutors then reviewed Amazon search records admitted as Exhibit 168.
Blackmer testified that records from Nov. 30, 2022, showed searches for “ceramic wall formula” and “wall hole repair kit,” followed by product clicks and a purchase.
The testimony then turned to Dec. 5, 2022.
According to the records, the account first searched for “combst knif,” which Blackmer testified Amazon automatically suggested as “combat knife.” He explained that the user accepted the suggestion before continuing to browse additional search results.
Blackmer testified that the records showed the user continued through multiple pages of search results before entering a new search for “hunting knife.”
The account later viewed several knife listings before adding a Smith & Wesson 9-inch fixed-blade knife to the shopping cart at approximately 3:30 p.m. Pacific Time.
The order history reflected that the knife was purchased for a total of $21.34, including tax.
Blackmer also explained Amazon’s internal action codes, which distinguish between searches, product clicks, purchases and items added to a shopping cart.
He testified that some actions labeled “K” indicate a product was opened from somewhere other than a search results page, such as another product page or an external link.
During cross-examination, Hutchinson questioned Blackmer about the limitations of Amazon’s records.
Blackmer acknowledged that the records do not identify what type of device was used to conduct searches or purchases.
The defense also presented a screenshot showing Amazon search suggestions on an iPhone, leading to testimony that search suggestions and scrolling behavior can differ depending on the device being used.
Blackmer testified that mobile phone users can scroll continuously through search results, while desktop users navigate between numbered pages.
He also acknowledged that Amazon’s autocomplete suggestions can change over time because the company regularly updates its search algorithms.
The retrial is expected to resume as prosecutors present additional evidence.
Follow the Vanguard on Social Media – X, Instagram and Facebook. Subscribe the Vanguard News letters. To make a tax-deductible donation, please visit davisvanguard.org/donate or give directly through ActBlue. Your support will ensure that the vital work of the Vanguard continues.
