A taped conversation of Lykken telling a fellow inmate in the South Dakota Penitentiary details of how he murdered Sheri Miller and Pam Jackson is a hoax, said Lykken's defense attorney, Mike Butler of Sioux Falls, in a Friday morning press conference.
Butler said during his meeting with reporters that charges against his client should be dismissed.
Attorney General Larry Long agreed in a release sent to media later Friday morning.
"The investigators have determined that a significant piece of evidence against Lykken was fraudulently manufactured by Aloysius Black Crow, a former cell-mate of Lykken, and a third inmate." Long said. "Black Crow tape recorded a conversation between himself and a third inmate, who pretended to be Lykken, and admitted to killing Jackson and Miller.
"Black Crow then gave the tape to law enforcement and told them that the voices on the tape were Black Crow and Lykken," he said.
Investigators believed Lykken, 52, may be responsible for the mysterious disappearance of Miller Jackson in May of 1971. He was indicted by a Union County grand jury in late July 2007. Lykken is already serving a 227 year sentence in the penitentiary for kidnapping and rape.
"Although Black Crow's testimony was not the only evidence on which the charges against Lykken were based, the state has decided not to proceed with a trial at this time," stated the announcement from Long's office. "Therefore the charges will be dismissed on Monday, Feb. 25."
Lykken was indicted on two counts of premeditated murder, two counts of felony murder and two counts of murder. The indictment charged that Lykken murdered Cheryl Miller and Pamella Jackson on or about May 29, 1971. Two other counts charged Lykken with rape and murder of Miller and kidnapping and murder of Jackson.
A number of leads have turned up over the years, ranging from reports of unidentified female bodies found in other states, to claims by captured serial killers that some of their victims were from South Dakota.
In 2004, the state DCI's newly formed Cold Case Unit decided to concentrate on the mystery of the two missing girls.
On Aug. 24, 2004, authorities from the sheriff's offices of Clay and Union counties, the Vermillion Police Department, and the South Dakota Department of Criminal Investigation began the execution of a search warrant at the farm of David Lykken's brother, Kerwyn Lykken, rural Alcester.
David Lykken was 17 and residing at the farm at the time of the girls' disappearance.
According to a 1991 investigative report in the Plain Talk, Miller and Jackson, both 17 and both juniors at Vermillion High School, had arranged to get together the evening of Saturday, May 29, 1971.
Jackson told her parents that they were going to visit Miller's grandmother at Dakota Hospital and then "go driving."
Miller told her half-sister, Rita, that after visiting the hospital, she and Jackson were going roller-skating at River Sioux, east of Vermillion, and were then going to a slumber party.
Miller was driving her grandfather's (Nick Jensen) 1960 Studebaker Lark. It was described as beige or light tan with SD plates 19-3994.
The girls were at the hospital visiting Pearl Jensen, Miller's grandmother, until about 9:30 p.m. They were seen one more time that evening by three classmates in a church parking lot at Garryowen, just east of I-29 at the Akron exit.
The girls met three acquaintances � Pat Gale, Steve Glass and Mark Logterman � at the Garryowen corner. The three young men were waiting for friends to arrive. They were headed to a keg party located south of Union County Park near a large gravel pit.
They never arrived.
There has been speculation over the years that the girls, while driving in the wrong direction at night, may have wound up in the Missouri River. Complicating the investigation immediately after the girls' disappearance was an unwillingness by many young people to talk to law enforcement.
Former Clay County Sheriff Arnold Nelson said the young people were protective. Talking to authorities was not a popular thing to do, especially when the questioning involved illegal parties, drugs and missing people.