Police investigating the disappearance of a 4-year-old British girl at a Portuguese resort are now considering the possibility that she might be dead, a senior official said Saturday.

Investigators say Madeleine McCann vanished May 3 from an apartment where she was sleeping with her 2-year-old twin siblings in a tourist complex on Portugal's southern Algarve resort coast while her parents were dining in the hotel's restaurant.

"In the past few days there have been some developments, some clues that have been found that could point to the possible death of the little child," the British Broadcasting Corp. quoted investigator Olegario Sousa as saying during an interview in Portugal.

"All lines of inquiry are open, but this line has a little more intensity," added Sousa.

Three days after she went missing, a Portuguese police spokesman based in the regional capital Faro said evidence pointed to a possible abduction which could have had "sexual" motives.

However, Portuguese newspaper Jornal de Noticias reported Monday that highly trained sniffer dogs brought from Britain found traces of blood on a wall in the room where the children had been sleeping on the night Madeleine disappeared.

The newspaper report, which did not cite sources, said investigators were analyzing if the blood was Madeleine's. It also said there was evidence someone tried to wipe away specks of blood off a wall.

Police in Britain are reportedly testing samples to determine if it is blood, and the find has fueled speculation that the child could have been harmed or murdered in the room.

Portuguese police and British detectives returned last week to search the home of 33-year-old Briton Robert Murat, the only named suspect in the disappearance.

Using rakes and hedge cutters, police cleared vegetation from the grounds of the house where Murat lives, which is about 100 yards from where Madeleine was last seen.

A hundred days after girl's disappearance, her parents joined a church congregation in prayers for her safe return in this seaside resort on Saturday.

Dozens of journalists and curious tourists crowded the approaches to the town's small church as the McCann family arrived for the service, one of several events planned to mark 100 days of the British girl's disappearance.