The parents of missing British girl Madeleine McCann on Saturday marked the 100th day since their three-year-old daughter disappeared from a hotel room in southern Portugal by taking part in a special service of prayers.
Madeleine's father Gerry told the gathering at a beachside church at Praia da Luz in Portugal's Algarve region, a top European holiday destination, that he and his wife Kate had not given up hope of finding their daughter alive.
But the detective leading the investigation acknowledged for the first time that police are probing the possibility that Madeleine may be dead instead of kidnapped as her parents believe.
"In the past few days, there have been some developments and some clues that have been found that could point to the possible death of the little child," Chief Inspector Olegario Sousa told the BBC in Lisbon.
"But at the moment, we are waiting for lab results on the evidence collected. All lines of inquiry are open but this line has a little bit more intensity," he said.
Forensics experts in Britain are currently examining evidence taken from the McCanns' holiday apartment, with the test results expected in the coming days.
Portuguese media have reported that traces of blood were found on the walls of the hotel bedroom at Praia da Luz from which Madeleine vanished on May 3, just before her fourth birthday.
She had been left alone in the bedroom with her twin two-year-old siblings while her parents dined with friends at a hotel restaurant.
Neither Kate and Gerry nor the friends they were on holiday with in the Algarve resort of Praia da Luz were being considered as suspects, Sousa said.
"It is so hard, every day has been so hard without Madeleine," said Kate, who carried her daughter's favorite pink stuffed animal in her hand, at the start of the prayer service attended by some 200 people.
"We have not given up hope that we will be reunited with her. We will not stop looking for her until she is found," Gerry said, his voice creaking with emotion. His speech was met with lengthy applause from the congregation.
Gerry, who wore a green T-shirt with a photo of Madeleine, said the past 100 days "had been the most difficult of our lives."
In an interview to be broadcast on the BBC yesterday, when asked if he could ever forgive the person who kidnapped his daughter, Gerry said that they would have to answer to God.
"Obviously we've had incredible pain over the past three months and we pray that Madeleine hasn't. Ultimately, it will be God who judges," he said.
While the couple attended the prayer service, the high-profile campaign to trace her whereabouts continued in Britain with English Premiership footballers wearing white T-shirts with Madeleine's photo on them as they warmed up for the first matches of the new season.
The T-shirts include the words "Don't You Forget About Me," from the Simple Minds song of the same name, which are being used in a new section on the Web site YouTube that the McCanns launched on Friday to help find missing children.
Players from English Premiership sides Liverpool and Aston Villa meanwhile wore yellow wristbands, the color that symbolizes hope, in solidarity with the McCanns during their match.