SISTER SLEUTH & PALS SOLVE GRISLY MYSTERY

HEARTSICK Heather Lane launched a desperate search for her missing sister, Katlyn Harp, in Pennsylvania — locating the tragic gal's corpse in just nine days and leading to the arrest of her brother-in-law, authorities say.

- 

Vincent Harp had insisted he had nothing to do with the disappearance of his wife, Katlyn Harp, who was last seen on June 19

Heather, 37, scoured a densely forested 40-acre property once owned by Katlyn's hubby, Vincent Harp, and found a large, padlocked metal box about 180 yards from the edge of a cliff, according to a criminal complaint.