MISHICOT -- A 16-year-old relative of Steven Avery will be charged along with Avery in the death of photographer Teresa Halbach, authorities said Wednesday night.
The boy was arrested Wednesday based on his own statements admitting his involvement, Calumet County Sheriff Jerry Pagel said.
Pagel said investigators have always considered the possibility that others were involved in Halbach's killing in addition to Avery, who served 18 years in prison for rape before DNA evidence exonerated him and he was freed in 2003.
"The 16-year-old juvenile admitted his involvement in the death of Teresa Halbach, as well as Steven Avery's involvement in this matter," the sheriff said.
Halbach, 25, disappeared after going to the Avery family's auto salvage yard near Mishicot on Oct. 31 to take pictures of a minivan Avery had for sale. Her sport utility vehicle was found later in the salvage yard, and bone fragments and teeth found in a burn pit were determined to be a DNA match to the woman.
Avery, 43, who repeatedly has denied any involvement in the death, was charged in November with first-degree intentional homicide, mutilating a corpse and possession of firearms by a felon.
Calumet County District Attorney Ken Kratz said Wednesday night that more information would be released when the teen is charged in adult court today as a party to first-degree intentional homicide. His initial court appearance is scheduled for Friday in Chilton.
The boy's name was not released. Authorities wouldn't say how he is related to Avery.
Pagel said the boy was interviewed Monday, and investigators decided to re-interview him Wednesday because of discrepancies in his statements.
Search efforts continued Wednesday night at Avery's residence and at an outbuilding, he said.
Kratz said the second arrest helped answer remaining questions about Halbach's death.
"The investigation today, in my opinion at least, has led to a conclusion or a definitive set of answers as to what occurred on the 31st of October 2005," he said.
The 16-year-old was in custody at a juvenile detention facility.
Avery remains held in Calumet County Jail in lieu of a $500,000 cash bond.
Last month, the Halbach family filed a wrongful death suit against Avery -- a day after Avery reached a $400,000 settlement of his lawsuit against Manitowoc County authorities who wrongfully convicted him for the 1985 rape.
Kratz was asked to prosecute the case because of Avery's civil lawsuit against Manitowoc County.
Halbach's brother Mike said he always suspected someone else was involved but the news of the arrest still came as a surprise.
"I wasn't ready to close the door on anything," he said.
Although he doesn't know the circumstances behind the boy's alleged involvement, he said he wished the teen would have brought it to light sooner.