Wolfe, 52, of Gaston is being charged with two counts of aggravated murder and two counts of kidnapping, police said.
“Everybody that’s been involved in this case continues to hope for the safe return of Karissa and William,” Upkes said.
The mother and son were last seen in west Salem, Upkes said. Her family reported them missing when she didn’t show up for work May 17.
Police, including divers, were searching a rural area southwest of Portland.
“It’s taking an incredible toll on everybody who’s out there. They’re working around the clock, following all leads,” Upkes said.
Court papers show Fretwell went to court last year to establish that Wolfe was William’s father. A DNA test verified her claim, and Fretwell then filed a petition seeking more than $1,000 a month in child support from Wolfe, court records show.