GALVESTON — After trying in vain to evade a Galveston Police Department vehicle for several blocks early Monday morning, Luis Argueta pulled over the car carrying him and his girlfriend on the 5300 block of Avenue L and bolted from the driver’s seat toward a vacant lot between two houses.

Argueta’s decision to flee his car proved fatal. After giving a verbal command for Argueta to stop, one of the officers pursuing him fired two rounds, striking and ultimately killing the 18-year-old.

Argueta was the 503rd person shot and killed by a police officer in the United States in 2018, according to a Washington Post database. Hours after Argueta was killed, 29-year-old Bobby Blade of Dallas was fatally shot by a police officer in Mesquite, putting the total number of people shot and killed by police on track to exceed the total number from each of the last three years.

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The Galveston County Sheriff’s Office did not give a justification for the shooting, citing an ongoing investigation alongside the Galveston County District Attourney’s office. The officer, who has not been identified, has been placed on routine administrative leave pending the outcome of the investigation.

Sheriff Henry Trochesset did not know what suspicious activity prompted city police officers to stop Argueta at a convenience store parking lot before he led officers on a brief chase.

“We’re trying to find that out too, what alerted (the officer) to think that was suspicious,” Trochesset said Tuesday.

The answer to that question may provide insight as to why Argueta fled in the first place. His girlfriend, Maryann Luna, told the Houston Chronicle that Argueta was generally “paranoid” around police and had a gun in the car.

At the time of his death, Argueta was facing three active felony charges: evading arrest detention with a previous conviction, possession of a controlled substance, and unlawfully carrying a weapon. He had been arrested eight times in the last six months. Luna said that’s why Argueta, whose nickname was “Taco” and whom friends described as kindhearted and generous, left the gun behind when he fled his car.

“I know he didn't mean no harm,” said a friend, Dorothy Diaz. “He just got out of jail for a pistol case, so I know for sure he didn't want to take another one. That's why he ran, because he was scared.”

A statement from the sheriff’s office on Tuesday confirmed that a weapon was recovered at the scene but did not indicate whether it was recovered on Argueta’s person or if it was found in the car.

The circumstances surrounding Argueta’s firearm are among the lingering questions that have left experts on officer-involved shootings stumped.

“One of the things the sheriff’s office is gonna be looking at is: What provoked the officer to pull the trigger?” said Larry Karson, an assistant professor of criminal justice at the University of Houston-Downtown. “Did [the officer] fear for his life, and if so, what was it based on? That’s the issue, besides going back and seeing why did you initiate this stop — what was your suspicion that led to it? Then we make this next jump when the individual runs, what caused you to fire? What was going on with the second officer? Did he have a different view of the situation? Was he behind? All of these come into play, and that’s where it’s gonna take some time.”

Karson said the police department’s delay in releasing a statement describing what led to the shooting is unusual. The police department released a two-paragraph statement on Monday about nine hours after Argueta was pronounced dead at UTMB Hospital in Galveston, saying only that a 3 a.m. traffic stop had led to an officer-involved shooting.

After the Chronicle reported the eyewitness account from Argueta’s girlfriend indicating he was shot while fleeing the officers, the county sheriff’s office issued a more detailed statement Tuesday confirming that Argueta was shot after being pulled over and running from the police.

Karson said when officer-involved shootings happen in major cities like Houston, police departments are typically quick to release details about the circumstances.

“What bothers me is that here we are two days later, and the department isn’t offering a basic explanation as to what happened,” Karson said.

Other experts praised the decision to have the sheriff’s office investigate, saying it was a positive step toward reaching an impartial conclusion in the Argueta case. In some cases, the investigating agency can refer such a case to the Texas Department of Public Safety, but Trochesset said his office will handle it for now.

The Galveston County Sheriff’s Office and Galveston Police Department often collaborate on investigations, but Jeremy Liebbe, a former Dallas police officer who now works as a law enforcement consultant, said merely working together does not necessarily indicate a conflict of interest.

“Criminal investigators, our job isn’t to prove them guilty or prove them innocent, it’s more archaeological. Whatever happened, happened. Dig through everything, go through it, put the puzzle together and report to, in this case, a grand jury first and ultimately a court, what do we have?” Liebbe said. “It’s quite possible that the sheriff’s office can have that objective neutrality, even if they do know the officers or have worked with them or have been involved with them in a court case or something.”

As with many officer-involved shootings, the victim’s criminal or arrest history can be used to defend an officer’s calculus on whether to open fire. A grand jury will ultimately decide whether to weigh Argueta’s arrest record against the circumstances of the case.

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Roberto Torres, an attorney assigned to represent Argueta in his felony cases, said police departments often rely on a suspect’s criminal history to “plant the seed” to justify a shooting.

“If they knew [Argueta’s arrest record] before the fact, knowing these things about him, an officer may be more cautious and if they’re more cautious perhaps they’re going to react to a perceived threat a little more quicker than you would if you didn’t have that knowledge,” Torres said.

But Dennis Root, a law enforcement trainer and nationally recognized expert in police practices and procedures, said that in the absence of that information about Argueta, Galveston police officers will have trouble justifying shooting him.

“Your decisions are based on what you knew at that moment in time you made the choice to pull the trigger,” Root said. “If the officer involved did not know that he was dealing with somebody who posed that immediate threat to the community at large, or to others — in other words his apprehension risked the lives of other people — if he didn’t know that, I don’t see how he could justify the application of deadly force given those variables. It doesn’t seem like it’s appropriate.”

Karson said the fact that Argueta had a gun in the car may have confirmed whatever initial suspicions the officers had in pulling over Argueta, but it is impossible to know whether the shooting was justified without testimony from the officer who shot him.

The presence of body cameras on the Galveston police officers and a dashboard camera at the scene could help solve some of the mystery.

“My understanding is there were two police officers at the scene so there ought to be at least two body cams,” Torres said. “If police officers were in separate patrol cars, there ought to also be two patrol car videos. (With) a total of four videos from different angles, you can get a clear picture of what the scene looked like at the time.”

Galveston police officers have been equipped with body cameras since 2016, but Sheriff Trochesset said the footage of the incident would not be released until after a grand jury had decided whether to indict the officer. And yet even clear footage of what happened to Argueta won’t answer many questions, like why the officer felt justified shooting him.

“(Body cameras) can’t tell you what the officer is thinking,” Karson said. “How much experience does the officer have? How long has he been on the street? Has he ever had any of these issues before? Does he normally work nights? Did he just get the job 90 days ago? All of this comes into play. At this point, what we have is a bunch of questions that one hopes the department will get answered quickly, because the community has a concern.”