In June, Lenexa police killed a Grandview man.
Jose Enrique Cartagena-Chacon, 25, was sitting behind the wheel of his car in an apartment complex parking lot with a gun in his lap when two officers arrived.
Callers to 911 said Cartagena-Chacon threatened two people with a pistol that turned out to be a pellet gun. Police didn’t know that when they rolled up, just that he was armed.
Both officers ordered Cartagena-Chacon to put up his hands and not touch the gun. Police say he started to point the gun at officers, then an officer on the driver’s side of the car shot him several times.
Johnson County District Attorney Steven Howe declined to charge the officers, and in a press conference announcing that decision, apparently referred to research from a company called Force Science, research one former prosecutor decried as “snake oil.”
“I think of the old fashioned, 19th century folks who head right into town with all sorts of cures for things that were actually phony,” said Steve McAllister, former Kansas U.S. Attorney in the first Trump Administration and current University of Kansas law professor.
The little-known, Minnesota-based for-profit company trains officers around the country, including dozens in Missouri and Kansas. It also provides expert witness testimony in use of force cases. But the entire business hinges on research it calls “high quality” aimed at understanding the “true nature of human behavior in high stress and deadly force encounters.”
Former Jackson County prosecutor Jean Peters Baker, now a plaintiff’s attorney, said Force Science has one aim for law enforcement officers.
“They're just interested in how we can clear you,” she said.
Force Science researches why cops shoot even if the subject isn’t firing at them, and even if the subject is unarmed. In the Lenexa case, the district attorney brought up one of the cornerstones of Force Science’s platform, delayed response.
“These officers are trained that there is always a delay in your response, and you're never going to get the first opportunity to react. You're going to be behind the ball,” Howe said.
Lewis Von Kliem, Force Science’s Chief Consulting & Communications Officer, says his company has saved more lives than any other law enforcement training.
Kliem graduated from the University of Kansas, and Washburn Law School, and is a former Topeka Police officer.
“A fast suspect can point and fire a weapon or attack with a knife in around 1/10th of a second. By comparison, the fastest visual reaction times are just over 2/10th of a second,” Kliem wrote in a Force Science essay posted in October.
For three months, KCUR has investigated why Force Science research is so controversial. But KCUR also discovered a cozy relationship between the for-profit company and the Lenexa police department.
Why Force Science research is controversial
In a 2013 ruling on a case in which an officer used force, California U.S. District Court Judge Jesus Bernal called Force Science research "nonscientific gobbledygook" and wrote that it enjoys “little or no acceptance within the relevant scientific community.”
A 2025 study from researchers at the University of South Carolina and Brown University concluded that “Reliance on Force Science in legal proceedings, training programs, and policing policies risks introducing unverified concepts into high-stakes decision-making contexts.”
The paper questions whether rigorous scientific methods support Force Science research.
“This is more like shaking the Magic 8 Ball and seeing the answer come up and saying, oh, I like that answer,” Seth Stoughton, a law professor at the University of South Carolina, and one of the authors, told KCUR.
Stoughton, a former officer with the Tallahassee Police Department, said Force Science works backwards from the outcome it desires. He likens it to a detective getting “tunnel vision” during an investigation.
“I may end up completely missing evidence that exonerates my suspect and inculpates somebody else,” he said.
For example, the “delayed response” justification that came up in Lenexa, he said, “ignores the degree to which good tactics can affect both the timing of the subject's action and the officer's reaction.”
Stoughton suggests this is based on Force Science research that says it only takes about 1/5th of a second to pull a trigger. Then-Lenexa police chief Dawn Layman, who retired this month to take over the police department in Breckenridge, Colorado, brought it up when she said the encounter with Cartagena-Chacon took only 10 seconds.
“Anybody in this room can pull the trigger on a weapon five times in one second. There's a statistic that is out there, right? So you have a very narrow window to make a decision,” she said.
Stoughton has two problems with that. The studies have a very small sample size and the “participants are not representative of the general population,” he said in an email.
Lenexa police department spokesperson Officer Danny Chavez declined to comment on the department’s relationship with Force Science.
“With Chief Layman’s impending retirement and the fact that a new chief has not yet been named, we do not have anyone available for an interview on this topic.”
“Do we want (police) to fear every citizen?”
The people doing the Force Science research aren’t trained for such things, McAllister told KCUR. More importantly, he said, “it always, always points in one direction, which is police never do anything wrong.”
Force Science vigorously defends itself against all attacks.
At a Police Executive Research Forum town hall meeting in November, shortly after the South Carolina paper was published, Kliem called it a hit piece. “None of these experts are aware of any research that contradicts or discredits the findings of Force Science. None,” he said.
He also says the authors have a history of promoting what he called progressive police tactics. “As activists, they unapologetically and necessarily advocate for a change in current law and police practices,” Kliem wrote in the July edition of Police Quarterly.
Former Jackson County prosecutor Jean Peters Baker said Force Science shapes the way officers interact with the people they serve.
“It sets up this dynamic where you have to presume the guy is going to shoot you,” she said. “Do we want them (police) to fear every citizen, or do we want them to have a little confidence that they can solve a problem without discharging a weapon.”
Kliem argues the kind of research Force Science conducts on police is also done by those who study pilots, medical professionals and the military. Despite suggestions by critics that the research is faulty, he says it is top-notch and peer-reviewed.
“Attempting to discredit Force Science studies does not negate the established consensus on human performance limitations and capabilities in force encounters,” he wrote in Police Quarterly.
The Lenexa business connection
Since 2021, Force Science has held training sessions four times in Lenexa municipal buildings. Officers from anywhere can pay for training.
The company had the potential to bill attendees a total of up to $524,000, according to contracts between Force Science and Lenexa police obtained with the Kansas Open Records Act.
The city charged Force Science nothing to use its facilities.
In fact, Lenexa police were obligated to help Force Science market the training.
“Both parties share the responsibility of actively promoting the event to ensure strong attendance,” according to the contract for the latest training in October.
It cost $1,695 to attend. The cost in 2023 was $1,395.
The contract also required Lenexa police to provide an audio-visual technician, a “waiting room or lounge” for Force Science instructors and snacks including coffee and soda.
In return for all of this, Lenexa police received seven “complimentary seats” in the last five years.
Kliem from Force Science said working with police departments is “more economical” and “pricing stays down” for participants.
And police officers are just more comfortable and honest in a police station, he told KCUR.
Lenexa also sent officers on the road for Force Science training.
Two officers spent three days in Columbia, South Carolina in April 2024 for a “Force Science Certification Court.”
One cost $1,695, and the other seat was complimentary, according to the city.
But the department paid $3,317 for travel, including flights, hotel, rental car, parking and meals.
Since 2020, 33 Lenexa officers have taken Force Science training, according to records from the Kansas Commission on Peace Officers' Standards and Training — known as C-POST — obtained with an open records request. That is the most of any agency in Kansas between 2020 and 2025.
Force Science training can be used to help fulfill the 40 hours of continuing education required by the state.
Force Science is “constantly trying to improve the industry,” Kliem told KCUR.
Former U.S. Attorney Steve McAllister doesn’t buy it. “I think personally, it's a waste of money. I'm not sure why law enforcement is training on it, because what it does is justify the shootings.”
The city would not comment on any of this. “During this time of transition with Chief Layman's retirement and the new chief not yet selected, neither I, nor the City will have any comment on this story,” Mayor Julie Sayers told KCUR in an email.
