(CNN) – An 8-year-old was found alive in sewage eight days after he went missing in Oldenburg, northwest Germany.

The boy, identified only by authorities as Joe, has been reported Missing In the afternoon of June 17.

The Oldenburg Police Department said Tuesday that Joe was pulled from the drain system after a passerby in the area heard noises coming from the manhole cover early Saturday morning and alerted emergency services.

Joe was found 300 meters from his home and taken to a nearby hospital, where he was treated for hypothermia and dehydration.

Police said they did not believe anyone else was involved in the incident.

An initial police report described Joe as having a learning disability. While searching, they said he might misread it as a game and stay hidden.

Joe’s last name has not been made public, in accordance with German privacy laws.

Workers set up a robot with a camera to try to determine how Joe entered the sewage system.

Immediately after the rescue, investigators began to comb the drainage system for evidence of her disappearance.

Authorities concluded that Joe most likely got into a concrete drainpipe while playing, then crawled into the drain system through a canal and got lost several meters later.

Investigators said that between the entrance to the drainage system and the place where Joe was found, there are drainage and crossing holes at regular intervals on which he was able to stand.

Joe told police in an opening statement that he became increasingly confused when he was stuck in the drain system and couldn’t find his way out.

“We are very pleased…really,” police spokesman Stefan Klatt said, according to CNN affiliate N-TV.

“He’s totally lucky. Of course, there was a possibility that we didn’t find the baby there. Maybe…if he didn’t make any noise or if that noise wasn’t heard, we probably didn’t find him there,” Klatt added.