Police have announced that Mark Bridger has been arrested on suspicion of murdering five-year-old April Jones.
Det Supt Reg Bevan said Mr Bridger remained in custody and would continue to be questioned.
Teams have spent the past few days searching around Machynlleth, where April went missing on Monday evening.
And officers now say they required only professional searchers to be involved in the hunt for April.
Det Supt Reg Bevan and Supt Ian John gave an update on the investigation at a press conference in Aberystwyth.
Bridger, 46, was arrested on Tuesday and is being held at Aberystwyth police station.
Det Supt Bevan said: "Mark Bridger has been arrested on suspicion of the murder of April Jones.
"He remains in custody in Aberystwyth and continues to be questioned.
"The arrest does not detract from our efforts to find her.
"Her family has been informed of this development and they continue to be supported by our specialist trained officers."
He renewed his appeal for information about Mr Bridger's movements and that of his vehicle.
"We are looking to trace the movements of Mark Bridger between 6.30pm on Monday and 3.30pm on Tuesday, and any sightings of him between these times," he said.
"We also need information regarding the movements of the blue Land Rover Discovery registration L503 MEP between these times."
Forensic examination is taking place on the vehicle.
"While this is a significant development, I appeal for information to find April," said Det Supt Bevan.
Supt Ian John said: "We want to acknowledge and are extremely grateful for the efforts of the community volunteers who have supported the professional searchers in trying to locate her.
"They have been a vital part of our team throughout this search operation. Quite frankly, their commitment has been an inspiration to us all.
"The dynamics of the search have now changed and due to the passage of time and the developments within the investigation, it is no longer appropriate for us to expect untrained members of the public to continue the search.
"So now we only require professional searchers to be involved in the ongoing search which continues in and around Machynlleth."
Earlier, officers were searching a farmhouse in the nearby village of Ceinws where he was known to be living most recently.