Specialist officers from Dyfed-Powys Police, along with others from other forces, have been searching the area in and around Machynlleth since the beginning of October.
The force says the search areas identified during the course of the investigation were completed on Friday.
47-year-old Mark Bridger has been charged with murder, abduction and intending to pervert the course of justice.
He denies all the charges.
More top news
After a cloudy start it will be a dry day today. The cloud will break up this afternoon, with some bright or sunny spells developing
An event was held this morning to mark the 80th Anniversary of volunteers from Wales joining the fight against fascism in Spain.
The region extended their unbeaten run at home in the league to five games.