BEXAR COUNTY, Texas – A 3D forensic analyst took the stand on Thursday in the trial of three ex-SAPD officers charged in Melissa Perez’s shooting death.
Angelos Leiloglou, the defense’s fifth witness, was first introduced to the defense and prosecution on Wednesday evening outside of the presence of the jury.
On Wednesday, the joint defense team mostly heard testimony from Kendall County Sheriff’s Office Lt. Thomas Matjeka.
Matjeka, 70, has 47 years of work experience in law enforcement.
Ex-SAPD officers Eleazar Alejandro, Alfred Flores and Villalobos are on trial for the shooting death of Perez, 46.
The department has since terminated Alejandro, Flores and Villalobos from the force.
Below is the timeline from Thursday’s court proceedings.
10:54 a.m. - Jurors entered the courtroom.
10:55 a.m. - Thom Nisbet, a co-defense attorney for ex-SAPD Sgt. Alfred Flores, called Angelos Leiloglou to the stand.
Leiloglou, the defense’s fifth witness, is a 3D forensic analyst who consults on trials and court cases.
10:58 a.m. - Leiloglou prepared a presentation for jurors to understand the science of 3D photogrammetry (the science of attaining reliable and accurate measurements from photographs) and reconstructing shooting scenes.
10:59 a.m. - Leiloglou said he received digital evidence, which includes “body-worn camera data and photographs,” from the scene of the Perez shooting to conduct his own examination.
11 a.m. - Leiloglou‘s presentation began playing before the court.
11:02 a.m. - Leiloglou told the court how the use of photogrammetry has made inroads in sports like tennis, football and soccer.
11:03 a.m. - “The idea here is that it’s all done by having multiple cameras, which, in this case, we have 15 body-worn cameras, right?” Leiloglou told the court. “(The) different perspectives allows you to see the same event that’s happening from different perspectives. Because we can do that, we can look through each camera and triangulate and find points where someone’s head is, where the gun is, knees, legs are in the 3D space as the events are happening.”
11:15 a.m. - Leiloglou explained 3D scene reconstruction as “digitally reconstructing a real-world scene to visualize, measure and analyze events with spatial and temporal accuracy.”
11:20 a.m. - Leiloglou began showing a picture from inside Perez’s apartment, which now has a new occupant, with a machine capable of taking 3D images.
“This is what it looks like,” Leiloglou told Nisbet. “It’s on a tripod. It spins around. You move it around from place to place because it’s a line-of-sight thing. If it can’t see it, it can’t measure it, so we have to move it around the site to get a full picture of the apartment itself.”
Because he described the apartment as a “very small” scene to measure, Leiloglou said he only conducted six 360-degree scans of Perez’s apartment.
“In most cases, I’ll probably do, like, 40 scans,” Leiloglou to the court. “But I could do what I needed to do here with six scans.”
11:25 a.m. - Leiloglou then told the court how he was able to take those (and other) 3D images and sync them up with the 15 SAPD officers’ body-worn cameras on scene at Perez’s apartment.
11:40 p.m. - In order to accurately see and recreate the incident on a 3D scale, Leiloglou said lens distortion from the body-worn camera video has to be corrected.
“We have to correct for lens distortion because we see without lens distortion,” Leiloglou said. “We don’t look around and see, you know, a straight line as curved. And, in this case, in the body-worn camera — hopefully, you’ve noticed that by now — things are curved that shouldn’t be curved. ... It solves for that lens distortion and corrects it."
11:50 a.m. - Leiloglou then showed the court multiple overhead 3D recreations of the ex-officers and Perez in relation to each other.
One of the recreations also estimated the distance between Perez and her patio door.
In all, 16 shots were fired at Perez. Two of those bullets struck her.
Here are the 3D recreations that showed where Perez was in her apartment as the eighth shot was fired in her direction.
Judge Ron Rangel, who is presiding over the trial, instituted a short break.
Jurors exited the courtroom.
12:02 p.m. - Jurors reentered the courtroom.
12:05 p.m. - The court then saw Leiloglou’s 3D recreations after the officers fired their 16th and final shot at Perez.
12:14 p.m. - Leiloglou showed the court Flores’ point-of-view, via 3D recreation, as Perez ran towards him and the patio door.
12:18 p.m. - Leiloglou then showed the court a split-screen 3D recreation of Perez and Flores’ points of view side-by-side.
“Can you talk a little bit about your margin of error rates? Initially — with measurement and things — is your rendered product here: would that be held to a degree of scientific certainty and precision?” Nisbet asked Leiloglou.
“Yes, it would,” Leiloglou said.
12:19 p.m. - Nisbet passed the witness.
Bexar County co-prosecutor Daryl Harris began cross-examining Leiloglou.
12:20 p.m. - Leiloglou said he went to Perez’s apartment to gather imaging for his investigation in September 2024.
12:23 p.m. - Leiloglou told the court that he was able to complete the 3D photogrammetry in October 2025.
12:24 p.m. - The presentation for the jury was finalized on Tuesday, Nov. 4.
12:33 p.m. - Harris asked Leiloglou how far Perez was from the wall at the 2:02:06 a.m. mark on June 23, 2023 — before the ex-officers fired at her.
12:34 p.m. - “We didn’t chart that out because we were only looking at when (ex-SAPD) officer (Eleazar) Alejandro fires his first shot,” Leiloglou told Harris.
“Could you have charted that distance, if you had been instructed to?” Harris asked.
“Yes,” Leiloglou said.
12:59 p.m. - Rangel instituted a lunch break for jurors.
2:02 p.m. - Jurors reentered the courtroom.
2:31 p.m. - Harris passed the witness. The joint defense team did not have any further questions.
Rangel excused Leiloglou from the stand.
2:32 p.m. - The defense called Dr. Ron Martinelli, a forensic criminologist, to the stand.
Martinelli is the joint defense team’s sixth witness.
2:33 p.m. - Rangel swore Martinelli in. Nisbet began questioning him.
2:51 p.m. - Nisbet asked Martinelli if he had an “expert opinion” on (SAPD) detective (Ronald) Soto’s investigation of the Perez shooting had any bias when he led it.
“Yes,” Martinelli said. “I found that both (implicit and confirmation bias) were profuse throughout the investigation.”
2:53 p.m. - Nisbet then asked Martinelli about how the body reacts to an “imminent threat.”
“This is fun stuff,” Martinelli began. “The body always wants to protect itself. And so, when faced with what we refer to as an ‘acute life threat,’ the body instantaneously, from the brain (and) throughout the body, the brain gives a trigger mechanism and ‘dumps’ with what we refer to as ‘survival chemicals’ into it. That’s completely involuntary. You don’t have any control of the ‘dump.’”
2:55 p.m. - Martinelli said Flores experienced some of those physiological effects when Perez began running towards him.
2:56 p.m. - “We talked about, for instance, ‘tunnel vision,’” Martinelli told the court. “A human being in a relaxed state can sense movement going out to about 180 degrees. Sense it, not necessarily see it and focus on it, but they can sense it.”
3 p.m. - Martinelli discussed an acronym that was first developed by an Air Force fighter pilot called OODA: Observe, Orient, Decide and Act.
“Those are the four components of response to a life-threat stimulus,” Martinelli said.
3:05 p.m. - Rangel instituted a short break.
3:17 p.m. - Jurors reentered the courtroom.
3:29 p.m. - With a fake gun, Martinelli attempted to recreate Flores’ response to Perez running toward him and the apartment patio door.
“With (ex-SAPD) Sgt. Flores, he’s pointing (a gun) in the direction while he’s going thorough the observe, orient (OODA) and he makes a decision,” Martinelli said. “But, when the decision is made, he does two things simultaneously. He attempts to create distance, and he gets caught in the corner. He can’t go back any farther, and the decision is made to engage. ... I’m literally cornered by my assailant, and I’m going to have to engage the assailant.”
3:59 p.m. - Nisbet asked Martinelli about whether he had an “expert opinion” on Alejandro’s actions on June 23, 2023.
“I believe that (ex-SAPD) officer (Eleazar) Alejandro, based on everything that I’ve reviewed, had a reasonable belief that Ms. (Melissa) Perez constituted an imminent, deadly force threat — or at least one that would cause serious bodily injury — and that lethal intervention was immediately necessary to protect Sgt. Flores," Martinelli said.
4:01 p.m. - Martinelli also agreed that ex-SAPD officer Nathaniel Villalobos believed it was “immediately necessary” to use lethal force to save Flores’ life.
Nisbet passed the witness. Jason Goss, a co-defense attorney for Villalobos, began cross-examining Martinelli.
4:14 p.m. - Martinelli recalled a piece of dialogue Perez had with some of the responding officers prior to the shooting.
“This is non-diagnostic. It’s very apparent that she (Perez) didn’t care,” Martinelli said. “Because if you remember the dialogue, the recorded dialogue, she said, ‘Shoot me!’ Who says that, right? Who says that to an officer when an officer is displaying force?”
4:31 p.m. - Martinelli told the court that, being in the ex-officers’ shoes, meant they had to make a “forced decision.”
“It’s a life/death decision,” Martinelli said. “So, it’s not only a life/death decision for the person that you’re shooting at, but a life/death decision for the person that you’re protecting. ... We are paid to take risks. We are paid to make deadly-force decisions in the blink of an eye, and you just have to calculate the risk vs. reward factor and make a decision.”
4:33 p.m. - Rangel ended court proceedings for the day. The trial is expected to resume on Friday morning.
Background
On June 23, 2023, Melissa Perez, 46, experienced a mental health crisis inside her Southwest Side apartment, where SAPD body camera footage showed she was fatally shot by ex-SAPD officers Eleazar Alejandro, Alfred Flores and Nathaniel Villalobos.
The case drew widespread attention and sparked debate over police response protocols.
Alejandro, Flores and Villalobos each face charges in connection with Perez’s death.
All three charged will be tried together, making for a packed courtroom.
Former prosecutor-turned-defense attorney Meredith Chacon said the plan to try all three together means each defense team has agreed on some kind of joint strategy.
“It indicates a sharing of resources, and they’re all working together on this defense,” Chacon said.
Each defendant has their own team of lawyers:
- Alfred Flores is represented by Thom Nisbet, Christian Neumann and David Christian.
- Eleazar Alejandro is represented by Ben Sifuentes and Mario Del Prado, a former division chief in the Bexar County District Attorney’s Office.
- Nathaniel Villalobos is represented by former Bexar County District Attorney Nico LaHood and his law partners Jay Norton, Jason Goss and Patrick Ballantyne.
As for the state, prosecutors include Felony Criminal Trial Division Chief David Lunan and Daryl Harris.
The trial is being presided over by Judge Ron Rangel of the 379th Criminal District Court.
Ahead of jury selection, a pretrial hearing became heated as attorneys sparred over key issues. Defense attorneys argued with prosecutors over which evidence and legal arguments should be allowed during the proceedings.
Among the issues discussed was a federal judge’s recent decision to dismiss a civil lawsuit against the officers — a ruling the defense wants jurors to hear about. Prosecutors opposed that motion.
Defense attorneys also objected to any discussion of the Castle Doctrine, or “protection of property” laws, during the trial. They argued it is irrelevant to the facts of the case.
Rangel has yet to rule on those motions.
If convicted, Flores and Alejandro each face up to life in prison. Villalobos, who is facing an aggravated assault by a public servant charge, also faces a maximum sentence of life in prison.
For a full look back at this case, watch the KSAT Open Court video below:
More coverage of this trial on KSAT: