Wisconsin serial killer dies in South Dakota

SIOUX FALLS, S.D. — A Milwaukee man convicted of killing seven women over a 21-year period has died in South Dakota, where he was serving a life prison sentence.

Walter Ellis, 53, died at a Sioux Falls hospital on Sunday of apparent natural causes, the South Dakota Department of Corrections said in a statement. The state Division of Criminal Investigation was looking into the death and an autopsy was planned.

Ellis was accused of killing seven women between 1986 and 2007. He pleaded no contest in 2011 in Milwaukee County to charges of first-degree intentional homicide and first-degree murder, and was sentenced to life in prison.

All seven victims were strangled, either by hand or with a rope or clothing tied around their necks. One also was stabbed.

Ellis was arrested in 2009 after police said his DNA matched semen samples found on six victims and a blood sample on a can of pepper spray discovered at the scene of the seventh slaying. Authorities have said they began to focus on Ellis after his name surfaced in connection with a number of unsolved homicides.

Ellis’ case exposed flaws in the state’s process for collecting DNA from convicted felons. Ellis’ DNA was missing from a state database even though he should have submitted a sample during an earlier prison stint. Authorities said Ellis persuaded a fellow inmate to submit a DNA sample in his place.

Police have said that if a sample had been taken from Ellis at that time, they may have been able to track him down before the last slaying, in 2007.

Ellis had been held in a South Dakota state prison under an interstate compact agreement. The Wisconsin Supreme Court declined to hear Ellis’ appeal earlier this year.