A 43-year-old homeless man has pleaded guilty to beating another man to death under a Minneapolis freeway overpass in a fit of jealousy.

Investigators determined that Duane J. Blackbull was angry because while he was in prison his girlfriend slept with the other man, 49-year-old Kristie J. Steinke, of Minneapolis.

Blackbull pleaded on Monday to second-degree murder in connection with the attack on Steinke under the Interstate 394 overpass near Dunwoody Boulevard on downtown’s western edge.

Blackbull had gotten out of prison on May 30, 2017, and killed Steinke on June 8. Two days later, law enforcement arrested Blackbull at Steinke’s memorial service.

Blackbull has agreed to a term of 17½ years. With credit for time since his arrest, he will serve the first 11 or so years in prison and the balance on supervised release. Sentencing is scheduled for May 18.

A witness told authorities that Blackbull bragged to him that he punched and kicked Steinke. Police found Steinke, unconscious, naked and lying on his stomach. Paramedics pronounced him dead.

Police searched a tent in the encampment where Blackbull had been staying and recovered bloodied jeans with his photo identification, a shirt and bloodstained shoes. DNA analysis of blood on the jeans revealed that it came from Steinke.