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Attorney General Marty Jackley

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Sioux Falls Man Receives 60 Years for Child Porn

Sioux Falls Man Receives 60 Years for Child Porn 

(Pierre) – A Sioux Falls man will be spending 60 years behind bars. Today Judge Gene Paul Kean sentenced Mathew Lee Mierkey, Sioux Falls, to the maximum penalty of 60 years in prison for possession of child pornography. 

Mierkey pleaded guilty in August to 30 counts of possession of child pornography. Because he was charged before the new state statute that raised the penalty for possession became effective, Mierkey was subject to a maximum penalty of two years in prison and a $2,000 fine per count. At the time of his arrest, Mierkey was already a registered sex offender for aggravated sexual assault charges out of Kansas. 

“This is the first Operation Avalanche sentencing we’ve seen in South Dakota. Research shows that those who collect child pornography will eventually want to act on their urges. Every time we convict one of these guys, we make South Dakota safer,” said Chief Deputy Attorney General Larry Long. 

Mierkey’s April arrest was the first to stem out of Operation Avalanche. Operation Avalanche was an investigation of a Texas based web site that sold child pornography. Operation Avalanche has led to the arrest of seven South Dakota men and more arrests are expected. In addition to Mierkey, those arrested include: John Mathew Peterson, Watertown; David Loren Wagner, Webster; James Robert Jackson, Rapid City; John Byron Martin, Belle Fourche; Charles P. Korstjens, Big Stone City; and Jerry Lee Wager, Rapid City. 

Peterson pled guilty to eight counts of possession in July. He is scheduled to be sentenced on Wednesday. Wagner, Jackson and Martin were all arrested in June. Wagner’s next court appearance is scheduled for Wednesday in the Day County Courthouse. Jackson also has his next court appearance on Wednesday in the Pennington County Courthouse. Martin is scheduled to have his next court appearance on October 24, in Butte County. 

Korstjens was also arrested in June and pled guilty to eight counts of possession of child pornography in September. He is scheduled to be sentenced on November 19 in Grant County. 

Wager was arrested in September and a hearing is scheduled for November 4, in Rapid City. 

Justin Douglas Brende, Mitchell, was arrested for possession of child pornography in July and in September he pled guilty to four counts. He is scheduled to be sentenced on November 5. Jeffrey M. Smith, Alexandria, was arrested in February. He pled guilty to four counts of possession and was sentenced to serve four years of probation. Neither of these arrests were the direct result of Operation Avalanche. Authorities were alerted to both men by informants. These arrests were all made through the joint efforts of the South Dakota Division of Criminal Investigation and local law enforcement agencies. The Governor’s Internet Crimes Against Children Unit assisted in the analysis of computers and evidence. Prosecution of these men is being handled jointly by the South Dakota Attorney General’s Office and numerous states attorneys.