The parents of four-year-old Madeleine McCann have condemned the decision by a Dutch newspaper to publish a letter claiming to know where her body is.
The search for Madeleine has been taken to Spain and Morocco
On his internet blog, her father said the letter and accompanying map should have been properly examined first.
Gerry McCann said the publication was "irresponsible" and "cruel" journalism.
Police are expected to search scrubland after the letter claimed Madeleine was buried nine miles from the Algarve resort where she was last seen.
Amsterdam-based De Telegraaf declined to comment on Mr McCann's criticisms.
The Dutch newspaper received the letter on Monday and passed it on to police, delaying publication of the information until Wednesday.
The letter identifies an area of scrubland 9.3 miles (15km) from where Madeleine vanished six weeks ago.
She was last seen in Praia da Luz on 3 May.
Mr McCann said: "We were extremely disappointed in the publication of the anonymous letter in The Telegraaf claiming to know where Madeleine is buried.
"Although all information will be taken seriously, we were very upset that the credibility of this letter had not been examined and, more importantly, [it was] published before the Portuguese police had an opportunity to investigate the claim, and search the area if appropriate without massive media attention.
"We feel strongly that this was an irresponsible piece of journalism and, even if it were true, is insensitive and cruel.
"One can imagine how upsetting it is for Kate and I to hear of such claims through the media and if every piece of information was published like this there would be nothing else in the newspapers."
Around eight plain-clothed police officers visited the village of Arao, which is 15km from Praia da Luz, on Wednesday evening.
There were no signs of any ground searches taking place on Thursday morning.
Locals say the country road that police stopped at on Wednesday is in an area which has not been searched before, said BBC correspondent Alison Roberts.
According to De Telegraaf, the Madeleine letter says the four-year-old, of Rothley, Leicestershire, is buried near a dirt track north of Odiaxere in the Algarve.
Ch Insp Olegario de Sousa confirmed Portuguese police were aware of the map and were doing "everything necessary".
He said: "There have been exchanges between Dutch police and us.
"We are checking the information like we check everything in this case for importance."
Dutch police are studying similarities between the new letter and one received last year by De Telegraaf pointing to the whereabouts of Belgian step-sisters Stacey Lemmens, seven, and Nathalie Mahy, 10.
The Belgian girls were murdered in June 2006 after they disappearing from Liege.
On the day the letter was received, police found their bodies at the spot indicated on an enclosed map.
A convicted paedophile, Abdullah Ait Oud, is now on remand awaiting trial for murder.
It is believed Madeleine was abducted from a holiday apartment while her parents ate at a nearby restaurant.