Former Illinois sheriff’s deputy Sean Grayson has died in prison while serving a 20-year sentence for the 2024 killing of Sonya Massey. Grayson’s attorney announced his death Sunday, August 23, but no cause of death has been released so far. Grayson had stage 4 colon cancer and had recently sought medical release from prison because of his condition.
The Illinois Prisoner Review Board rejected that request in July. Grayson was convicted of second-degree murder in October 2025 and sentenced to 20 years in prison in January 2026. He was 32.
What was Sean Grayson’s cause of death?
There is no confirmed cause of death for Sean Grayson at this time. His attorney announced that he died in prison, but did not immediately provide further details about what happened.
Grayson had been battling advanced colon cancer. According to Capitol News Illinois, he was diagnosed in 2023, and the cancer later spread to his liver and lungs. His health became a major part of his legal case this year as he asked to leave prison on medical grounds.
His request was denied by the Illinois Prisoner Review Board in July. The three-member board voted unanimously against his medical release, meaning Grayson remained in custody until his death.
{{/usCountry}}His request was denied by the Illinois Prisoner Review Board in July. The three-member board voted unanimously against his medical release, meaning Grayson remained in custody until his death.
{{/usCountry}}Why was Sean Grayson in prison?
Grayson was serving a 20-year sentence after a jury found him guilty of second-degree murder in the shooting death of Sonya Massey.
Massey, 36, had called 911 in July 2024 to report a possible prowler near her Springfield, Illinois, home. Grayson and another deputy responded to the call and later entered her home.
Body-camera footage showed Grayson confronting Massey in her kitchen. During the encounter, Massey said, “I rebuke you in the name of Jesus.”
Grayson then responded, “I'll fing shoot you right in the fing face” before firing his gun. Massey was struck and killed.
Grayson later maintained that Massey had attacked him with a pot of boiling water. In his medical-release application, he wrote, “While inside she attacked me with a pot of boiling water and I fatally shot Mrs. Massey.”
Why did Sean Grayson seek medical release?
Grayson applied for release under Illinois’ Joe Coleman Act, which allows some seriously ill prisoners to seek release under certain conditions.
His lawyers cited his advanced cancer. However, the Prisoner Review Board rejected the request in July, keeping him in prison to serve his sentence.
Sonya Massey’s family had opposed his release. Her cousin Sontae Massey told Capitol News Illinois in June, “He's a killer. I apologize that he must suffer, but he has to pay for what he did.”
Grayson’s death now comes less than seven months into his 20-year sentence. His attorney has not yet given further details about when or how he died.