EVANSDALE, Iowa (KCCI) - It has been nearly seven years since two cousins from Evansdale first disappeared.
A father of one of the girls believes the case will be solved, according to KCCI.
Elizabeth Collins, 8, and 10-year-old Lyric Cook were out riding their bikes when they went missing July 13, 2012.
Hunters discovered the girls' bodies in a secluded wooded area about 20 miles away, five months after their disappearance.
To date, authorities have looked at 300 sex offenders and interviewed more than one-thousand people.
Drew Collins meets with FBI agents for coffee about once a month to check-in. Authorities remain tight-lipped on the details - but tell him they are determined to find his daughter's killer.
Authorities have never revealed the cause of death or autopsy results. They believe that is only information the killer would know.