A former liquor store clerk pleaded guilty Monday to recklessly causing the death of a 29-year-old customer who walked into a Kansas City Northland store in 2022 to buy cigarettes and never walked out. Mark Delano Shelton, now 58, admitted under a plea agreement that he recklessly caused the death of Dustin Niehouse by shooting him at the Cloud9 Liquor convenience store, a killing that had originally been charged as second-degree murder.
A Nearly Four-Year Path to a Guilty Plea
Clay County Circuit Judge Timothy J. Flook accepted Shelton's plea to first-degree involuntary manslaughter, according to The Kansas City Star. Flook has set sentencing for 3 p.m. Wednesday. Police responded to the fatal shooting shortly after midnight on November 28, 2022, at the store, which sits at 4305 N. Antioch Road in Kansas City's Chaumiere neighborhood, and Shelton was arrested just over six months later. A grand jury indicted him in June 2023 on charges of second-degree murder and armed criminal action, and he had been scheduled to stand trial on those counts in Clay County Circuit Court before this week's plea.
The case took a winding route to reach that point. Shelton previously pleaded guilty to first-degree involuntary manslaughter in March 2025, only to be allowed to withdraw that plea two months later. That withdrawal caused the original second-degree murder and armed criminal action charges to be reinstated, and prosecutors ultimately filed a substitute information charging one count of first-degree involuntary manslaughter, the charge Shelton pleaded guilty to Monday — a lesser charge than the second-degree murder count he had originally faced.
What Happened Inside Cloud9 Liquor
According to attorney statements reported by the E. Rex Bradley Law Firm, Niehouse had left home with his dog shortly before midnight to buy cigarettes, dressed in sweatpants and a hooded sweatshirt. He was carrying only two packs of cigarettes, a small bottle of liquor, a lighter, keys, and a debit card — he was completely unarmed when he was shot. Plaintiff attorneys disclosed that Niehouse suffered five gunshot wounds, striking the left side of his nose, the left side of his neck and upper chest, his left forearm, and twice in his right thigh.
The same attorney accounts note that Cloud9 Liquor's security cameras were disabled at the time of the shooting, and that Shelton turned off the store lights, locked the doors, and called his manager rather than 911 immediately afterward. Witnesses reportedly said Shelton locked the store and turned out the lights. The cameras were disabled, so there was no video evidence of the confrontation inside the store.
A $1 Million Settlement Before the Criminal Case Concluded
Separate from the criminal proceedings, Groceries 4 Less LLC reached a $1 million wrongful death settlement with Niehouse's mother, Valorie Niehouse, that Judge Flook approved in October 2024. The out-of-court settlement, reported by the E. Rex Bradley Law Firm, included more than $14,000 for funeral and ambulance expenses and did not include an admission of liability.
What Shelton Faces at Sentencing
Under Missouri law, first-degree involuntary manslaughter is a Class C felony that occurs when a person recklessly causes another's death, carrying a sentencing range of three to 10 years in prison — far short of the far harsher terms associated with second-degree murder convictions. Shelton now faces that three-to-10-year range. Missouri courts' published case materials show that Brian Geoffrey Massa previously appealed a conviction for first-degree involuntary manslaughter, illustrating that the offense has been litigated in appellate cases. Missouri Courts records show that a separate case involving Zachary ... included jury instructions on first-degree involuntary manslaughter, the lesser-included offense of second-degree involuntary manslaughter and armed criminal action. Missouri's armed criminal action statute would have added a mandatory, consecutive prison term of at least three years without parole eligibility had that charge, which prosecutors had reinstated before the final plea deal, gone forward to conviction.
The killing fits into a broader pattern of gun violence tied to disputes in Kansas City's retail and public spaces. Kansas City recorded 171 homicides in 2022, the year Niehouse was killed, making it the second-deadliest year in the city's recorded history at that point, according to Kansas City Police Department data reported by Police1. The Police1 report's 2023 homicide data identified arguments as the leading contributing factor and guns as the leading weapon, and KCPD leadership has emphasized reducing such disputes as a key public safety focus.
Shelton's sentencing is scheduled for 3 p.m. Wednesday in Clay County Circuit Court, where Judge Flook will determine how much of the three-to-10-year range he will serve for a killing that took nearly four years to resolve.
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