El Dorado ? A prosecutor says it will be several months before she decides whether to file charges in the case of an 11-year-old boy whose disappearance went unreported for nearly a decade.

Butler County Attorney Jan Satterfield said Tuesday that while the investigation into the disappearance of Adam Herrman is “solid,” the case is complex.

“I want to assure the public that this case is a top priority,” Satterfield said. “It’s actively being worked, every week.”

Investigators turned their findings over to Satterfield a month ago. Earlier this year, Satterfield said the case could result in murder charges. She said she must be sure that the case would be ready for trial, and that any evidence would be admissible in court.

As chief prosecutor, Satterfield can decide whether to file charges or take the rare step of asking Butler County District Court judges to convene a grand jury.

Adam Herrman was 11 years old when he disappeared in 1999 from a mobile home park in Towanda, 25 miles northeast of Wichita. His 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.

Butler County Sheriff Craig Murphy has said he believes his office has found enough evidence to charge the boy’s adoptive parents, Valerie and Doug Herrman. Searchers found no human remains, but the sheriff declined to discuss what evidence they had uncovered.