SIOUX FALLS, S.D. (AP) -- 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.
The South Dakota Department of Corrections say 53-year-old Walter Ellis died at a Sioux Falls hospital on Sunday, of apparent natural causes. An autopsy is planned as standard procedure.
Ellis was accused of killing seven women between 1986 and 2007. All seven victims were strangled. One also was stabbed.
Ellis pleaded no contest in 2011 to first-degree intentional homicide and first-degree murder. He was sentenced to life behind bars. An appeals court upheld his conviction, and the Wisconsin Supreme Court declined to hear Ellis' appeal earlier this year.
Ellis was being housed in a state prison in South Dakota under an interstate compact agreement.