In 1999, 11-year-old Adam Herrman disappeared from his adoptive parents' mobile home on the south side of town.

But investigators didn't discover the boy had been missing until about a year ago — after his older, adoptive sister told authorities she was concerned about him.

His disappearance became public in late December 2008, when Butler County investigators began digging in the mobile home park, looking for human remains.

Adam's adoptive mother denied allegations from close relatives that she had physically abused him before he disappeared.

Now, a year later, the mystery remains unsolved.

Authorities say they continue to work on the case.

In a recent interview, Butler County Attorney Jan Satterfield said she expects to make a decision on charges within the next year. Nearly a year ago, she said Adam's adoptive parents were suspects in his disappearance. In some ways, Satterfield said, the case gets stronger with time.

"There is no statute of limitations on murder,'' she said. "And for every year that passes, I think it only strengthens our case, especially given the extent of publicity.

"There's simply no trace of him anywhere. Time's our friend in bodiless cases. Another year's passed — no Adam Herrman, no sight of Adam Herrman."

The discovery of the disappearance and the ensuing child abuse allegations drew wide attention. A year later, The Eagle continues to receive e-mails — some from as far away as South Africa — asking about the status of the case.

How case unfolded

Satterfield said that within the next year, she expects to file charges or submit the case to a grand jury so it could consider bringing indictments.

"We continue to make progress in the case," she said, "and I do understand the importance of it, and I do desire to have movement on this case in the next year."

She declined to say what charges might be filed.

Investigators turned the case over to Satterfield last spring. She had hoped to present the case to a grand jury by this past December, but her office has been busy meeting deadlines on three homicide cases in which charges have been filed, she said.

Warner Eisenbise, the lawyer who represents Adam's adoptive mother, Valerie Herrman, said, "My only comment is all that's been said is certainly conjecture and nothing more.... Common sense isn't sufficient to find guilt beyond a reasonable doubt."

Laura Shaneyfelt, lawyer for Adam's adoptive father, Doug Herrman, agreed with Eisenbise.

"I think prosecutors should always be careful in bodiless cases and not jump to conclusions," she said. "Just because someone has disappeared does not mean they have been murdered."

The Herrmans continue to assert that they are innocent, their lawyers say.

In an interview with The Eagle last January, Valerie Herrman, then 52, said that in early May 1999, when Adam was 11, he ran away from their Towanda mobile home and didn't return after she spanked him with a belt. She said she didn't report him missing because she feared it would cause her and her husband to lose custody of Adam and their other children.

Relatives said that Valerie Herrman told them that Adam, who was being home-schooled, was no longer at home because he had been returned to state custody.

After his older, adoptive sister came forward and expressed concerns about him to authorities in late 2008, Butler County investigators searched for remains. Using search dogs, they probed in woods along the Whitewater River, but didn't find anything, Butler County Sheriff Craig Murphy said.

Recently, Murphy said, when asked about the case: "We have not forgotten about it. We are still working on it. It is an important case."

Biological dad's view

Adam's biological father, Irvin Groeninger, said he is frustrated that there has been "no closure" in the case a year later.

Still, Groeninger said, he thinks authorities are doing everything they can. He said he hopes that charges will be filed.

"I'm hoping that there will be justice served on this."

And he said he would welcome renewed media attention on the case.

Asked whether he thinks his son could be alive, he said, "I feel he would have been heard from by now."

The money issue

Another unresolved matter is money the Herrmans continued to receive as an adoption subsidy from the state — after his disappearance.

Court records show that the Herrmans continued to list Adam as a dependent in court documents. Valerie Herrman told The Eagle that they continued to accept $700 monthly adoption subsidy payments for Adam until his 18th birthday in 2005 — six years after he disappeared. Adam would be 22 now.

Satterfield would not comment on whether charges could be filed over that issue.

She said she expects to meet on the case with child abuse experts this month. She said she has obtained a number of statements in addition to extensive information that sheriff's investigators have collected.

"Too much has been invested in this case, professionally and personally, to just forget about it.

"I just think it is chilling when kids can disappear without a trace."

A neighbor's thoughts

At the mobile home park in Towanda where Adam disappeared, residents said they haven't seen investigators doing any more digging.

Garren and Nikki Hutchison moved into the park around the time Adam disappeared. They live a block from where he lived.

They watched early last year as news crews reported on the search for remains. They know the case initially drew wide media attention.

"I think as national as it went, if he was alive, he would have said something," Garren Hutchison said.

Adam would be an adult now, he said, and would have no reason not to come forward. He said somebody knows what happened to him.

"We're praying that the situation gets solved one way or another,'' Hutchison said.

"It's not right for there not to be peace for that young man if he is not alive any longer."