The search for missing seven-year-old Daniel Entwistle is not being scaled down, police said on Tuesday.
Daniel has been missing for three weeks
Daniel disappeared from his home at Great Yarmouth, Norfolk, more than three weeks ago.
Senior officers who met to review the case decided the search should continue on its existing scale.
About 50 officers are involved in ground and water searches with another 50 following up lines of inquiry.
So far police have received 1,000 calls from the public which have thrown up 1,700 lines of inquiry.
They have also searched 234 premises on the Barrack Estate.
Officers said there was still nothing to indicate what happened to Daniel, whose bike was found near the River Yare, although they fear he fell into the river.
Daniel's family told the BBC that they were "bearing up and prepared for the worst".
The said they were grateful for police efforts and just wanted an end to the uncertainty.
Police have widened their search by posting pictures of possible witnesses captured on CCTV.
Nearly 100 people were taped near where Daniel disappeared.
Police said they hoped the new posters will prompt key witnesses to come forward.
Earlier this month, the boy's grandfather, Keith Button, urged visitors to the resort town to check photographs and video pictures they may have taken in order to find some clue to his whereabouts.
Daniel has a strong northern accent and is described as 3ft 2in tall, with a thin build and light brown cropped hair.