Towanda ? Investigators on Saturday ended their last scheduled search for the remains of a Butler County boy who disappeared 10 years ago.

Investigators searched for about an hour Saturday in an area northwest of Towanda along the Whitewater River. Butler County Sheriff Craig Murphy said the search was based on a tip. No remains were found.

The area is near the Towanda mobile home park where Adam Herrman was living with his adoptive parents when he disappeared in 1999 at age 11.

Three previous searches have focused on the banks of the Whitewater River. Investigators also have searched at the mobile home lot where the Herrmans lived before they moved to rural northwest Sedgwick County.

Murphy said Saturday was the last planned search of the Towanda area unless they get another tip.

Murphy said he expects a “healthy overtime bill” for detectives who have worked 12- and 16-hour days to solve Adam’s disappearance. But he said he didn’t have cost figures available to cite.

When a resident recently asked, “What is this costing the county?” Murphy said he replied, “If it was your family member, what would you want us to do?”

He said volunteers — including search-dog handlers and anthropology experts looking for remains — have kept search costs lower. The volunteers are sacrificing time with their families, he said.

The searches have been conducted on Saturdays to help accommodate volunteers’ schedules, Murphy said.

Butler County Attorney Jan Satterfield has said that Adam’s adoptive parents, Valerie and Doug Herrman, are suspects in the case and that the investigation could result in murder charges, with the underlying allegation being child abuse.

Several of Valerie Herrman’s close relatives have said they saw her abuse Adam over the years. She left a telephone message at The Wichita Eagle this week saying her relatives are lying when they allege abuse. The Herrmans and their attorneys say they are innocent.

Adam’s disappearance became known late last year after his older, adoptive sister voiced concerns about him to authorities.

Investigators said they could find no records or indication that Adam was still alive.