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DENVER (KDVR) — The mother of the victim murdered near Coors Field last year has grown frustrated in searching for answers about her daughter’s death. Ana Thallas posted on Facebook that her daughter was murdered with a gun that belonged to a Denver Police Department sergeant.

Michael Close, 36, is accused of shooting 21-year-old Isabella Thallas and her boyfriend, 27-year-old Darian Simon, outside an apartment complex in the Ballpark neighborhood in June 2020. Thallas died at the scene, and Simon was shot twice but survived.

Ana Thallas said, “I don’t even know where to start with this because it’s been such a nightmare. I was led to believe it was an AR-15, but now we’ve been told Isabella was murdered by an AK-47 that belonged to a Denver police sergeant.”

Isabella Thallas. Credit: Thallas family

FOX31 has confirmed the gun used in the murder had belonged to a Denver officer.

The Denver Police Department released a statement that said, “Close, a friend of a Denver Police officer, took the rifle from the officer’s home without the officer’s knowledge or permission. Upon learning his rifle was missing and that it may have been used in this homicide, the officer notified investigators that the rifle belonged to him. The rifle was not issued to the officer by the Denver Police Department.”

Ana Thallas said she does not believe DPD.

“No, I don’t believe that at all. I believe he sold it to him. To have an AK-47 missing… for you to be a police officer, not just an officer, but a sergeant. And to have that missing, no. I would know automatically. That just doesn’t go missing. It doesn’t happen that way. I think the thing that disgusts me the most, had he acted — the oath that he took to serve and protect — Isabella could still be alive,” Ana Thallas said. “She was kind, patient, loving, forgiving, unique, a trend-setter, a leader and missed. She is missed tremendously. A life taken for no reason — no reason at all. I am her mother, I will not let this go until I see justice all the way through for everyone involved in this case. I’ve had enough.”

Detectives said the shooting followed an exchange of angry words between Close and Simon after Simon’s dog pooped in a rock garden outside Close’s apartment complex at 3001 Fox St.

Simon and Thallas were walking their dog around 11:40 a.m. when Close opened his window and allegedly yelled, “Are you going to train that f—ing dog or just yell at it?”

Soon after police arrived on the scene, they were met by a woman named Chelsea Thompson, who identified herself as Close’s girlfriend.

Thompson told police Close was driving toward the mountains in his black Mercedes SUV and police were able to ping Close’s cell phone to find his exact location.

Jefferson County sheriff’s deputies arrested Close at Pine Junction.

During the investigation, police also recovered an assault-style weapon, a Glock 17 and a shotgun, plus lots of ammunition and high-capacity magazines that can hold more than 15 bullets, which are not legal in Colorado unless they’re grandfathered in.

One long-time friend told police Close had texted him after the shooting to say, “Dude, I fu–ed up really fu–ing bad, there’s no going back from this now.”

That same friend told police he had plans to take Close to see a therapist on the day of the shooting after Close had revealed to him that he had been sexually abused by his biological parents and suffered from a personality disorder.

Another friend told police that Close confessed to him by text that he had “just snapped.” That friend told police Close had confided spending time in a mental institution at the age of 12 and had concerns about harming himself, but the friend said he never thought Close would harm others.

Detectives found Close had no criminal history, but had police contact in 2014 for a mental health hold. No details were released at the preliminary hearing indicating whether Close actually was taken to a mental facility six years ago or not.

Close faces charges for two counts of first-degree murder, two counts of attempted first-degree murder, two counts of first-degree assault, nine counts of using a prohibited high-capacity magazine during a crime, two counts of prohibited use of a firearm and one count of disorderly conduct.

“It’s hard. Obviously we want justice served in the most speedy time frame as possible. It’s just part of the process. It’s hard, it’s hard on the family. Every time a court case comes up or is continued, the wound gets reopened, the Band-Aid gets re-ripped off and you re-live every single time,” said Josh Thallas, Isabella’s father.

He said he wants to keep the focus on the prosecution and his daughter, who he described as “an amazing soul, still is an amazing soul. For only being on the face of the earth for 21 years and one day, she sure made and impact on so many, so many human beings in the most powerful way. Her one word was always ‘others.’ That’s truly the human being she was. She spoke to everybody with kind, gentle words. I can’t find any human being that had an issue with her. It was not in her character. She challenged us all the time to be a better rendition of the person we were the day before.”