The abductor is familiar with the party area and gate at Meyer's Lake park, and with Seven Bridges County park. Almost everyone agrees that only someone local would know both areas. Local could mean Waverley, Stratford, Waterloo, Evansdale ...
As far as I recall, both the Meyer's Lake party spot, and the Seven Bridge youth camp, ended around the early 1990s. They were youth and young adult party and organized sports locations.
What age would someone be in 2012 if they were 14 years old in 1991 (parties/youth camp)? Born between 1973 and 1977, age 51-55 today.
Abducting two girls at once seems bold for a first-time. It might have been his crowning glory, maybe there won't be another murder like this that exposes him (like Morgan Harrington and Hannah Graham). In 2012, at the time of the double murder, a 55 year old today would be 41 years old. If he grew up in Waterloo/Evansdale, he would have been a teenager when Seven Bridge County park was a youth camp, and Meyer's Lake was a party spot (per Lyric's grandmother). Double abduction murder of children doesn't seem like a first-timer.
I looked at Iowa cold cases from 1990 to present and didn't see anything similar. From reading about murderers for decades, an opinion, but I think some murderers murder closer to home (Bundy was different) the more often they get away with it.
Unsolved murders in Iowa from the year 2000 to the present.
iowacoldcases.org