Indiana State Police said they are discussing the murders of Libby German and Abby Williams with investigators in Fort Wayne.
Bodies of the two teens were discovered on a hiking path on Valentine's Day in 2017.
On Sunday, Fort Wayne police arrested 59-year-old John Miller in the 1988 murder of 8-year-old April Tinsley, after D-N-A evidence led them to him.
Indiana State Police Sergeant Kim Riley told ABC News Wednesday: "About all I can say, is we are discussing the case with them and talking. No other comment to say at this time."