Andrew Ellmaker, convicted of murdering Johnson County social worker Teri Lea Zenner in 2004, was found dead in his cell at the El Dorado Correctional Facility on Aug. 18, the Kansas Department of Corrections confirmed.
Ellmaker, 39, was found unresponsive. Prison staff and emergency medical personnel attempted life-saving measures but could not revive him, according to a KDOC statement. The cause of death is pending an independent autopsy, and the Kansas Bureau of Investigation is investigating.
Ellmaker's death came one day after the 22nd anniversary of Zenner's killing.
The 2004 murder
Zenner, 26, was a social worker with the Johnson County Mental Health Center. On Aug. 17, 2004, she visited Ellmaker's Overland Park home for a routine check to ensure the then-17-year-old was taking medication prescribed for schizotypal personality disorder, the Johnson County Post reported.
Court records show Ellmaker attacked Zenner with a knife, stabbing her multiple times. His mother tried to intervene and was stabbed four times. When the knife bent, Ellmaker retrieved a chainsaw from his closet and continued the attack on Zenner, according to Fox 4. A coroner determined Zenner was likely already dead before the chainsaw attack.
Ellmaker's mother survived and escaped to a neighbor's home to call for help. Overland Park police arrested Ellmaker without incident after he attempted suicide by ingesting pills and set Zenner's car on fire.
Conviction and sentence
Ellmaker was charged as an adult with premeditated first-degree murder and aggravated battery. He was sentenced July 19, 2007, to a "Hard 50" sentence for the murder conviction, meaning a minimum of 50 years before parole eligibility, plus an additional 40 months for the battery conviction, totaling nearly 53.5 years. The Kansas Supreme Court affirmed the conviction in December 2009.
During 19 years in state custody, Ellmaker served time at four facilities and was the subject of nine disciplinary reports, including possession of a weapon and fighting.
Zenner's legacy
Zenner's husband, Matt Zenner of Olathe, spent years advocating for legislation to protect social workers. In April 2010, Gov. Mark Parkinson signed Senate Bill 25, making Kansas the first state to require safety training as part of social worker licensure renewals.
"What happened to Teri shouldn't happen to anyone," Matt Zenner said at the April 2010 signing ceremony at the Kansas Statehouse.
Zenner's father, Andy Mathis of Gardner, said at the same ceremony that his daughter was nearly finished with a master's degree in social work at the University of Kansas when she was killed.
A memorial garden honoring Zenner was originally dedicated in 2006 at the Johnson County Mental Health Center and rededicated in May 2022 at The Recovery Place, 11120 W. 65th St., Shawnee. On Aug. 17, 2026, the center posted a tribute honoring Zenner as a beloved staff member whose compassion continues to be remembered by colleagues.
The KDOC and KBI investigation into Ellmaker's death remains open, with no timeline announced for autopsy results.
