The disappearance of British toddler Madeleine McCann nearly seven years ago captivated the world, but the international spotlight revealed few concrete clues.
The 3-year-old, who vanished while on vacation in Portugal with her family, has never been found.
But on Wednesday, London's Metropolitan Police shared a new lead in the case: Detectives "identified a potential linked series of 12 crimes," occurring between 2004 and 2010, in which a male intruder gained access to holiday villas in the area where Madeleine's family had been vacationing.
Officers appealed for information on the suspect's identity, which they believed could lead to clues about what happened to Madeleine after her parents, Kate and Gerry McCann, left her and her two siblings in their apartment in the Algarve resort of Praia da Luz while they ate dinner at a restaurant 150 feet away.
The new information is considered a potential major break in the investigation, but promising leads have provided false hope in the past. Here are other developments that have popped up in the mystery over the past seven years:
May 5, 2007: Two days after Madeleine goes missing, police reveal that they believe she is still alive and being held near the scene of the crime. They also have a sketch of a suspect, but media report the drawing is vague.
May 15, 2007: A British man, Robert Murat, is taken to the police station in Portugal for questioning, but is later released.
May 25, 2007: Law enforcement ask for information about a white male, between the ages of 35 and 50, who was spotted near where Madeleine disappeared.
June 16, 2007: A British couple report they saw a blonde girl in Valletta, Malta. It's one of a number of possible sightings reported of Madeleine, who has a distinct black mark in her right eye, and detectives launch a full-scale investigation.
Aug. 11, 2007: Police acknowledge for the first time that Madeleine could be dead.
Sept. 7, 2007: Madeleine's mom, Kate, is officially declared a suspect after 10 hours of questioning by Portuguese police. The following day, the girl's dad, Gerry, is also declared a suspect. But by Sept. 19, 2007, the district attorney general of Evora, Portugal, rules there isn't enough evidence to keep questioning the McCanns in their daughter's disappearance.
Jan. 20, 2008: Kate and Gerry McCann release a new artist's sketch of a man they claim may be involved in the disappearance, based on a description by a British vacationer of a man acting suspiciously in the Praia da Luz holiday resort about two weeks before Madeleine went missing.
Aug. 4, 2008: Thousands of pages of evidence from Portuguese police are made public for the first time, revealing witness statements of loads of previously unpublished alleged sightings of Madeleine.
May 1, 2009: An age-progressed image of Madeleine is broadcast on "The Oprah Winfrey Show." Her parents also appear on the show.
May 22, 2009: Detectives hired by the family are investigating a convicted pedophile named Raymond Hewlett in the disappearance, McCann family spokesman Clarence Mitchell says. Hewlett is later ruled out.
Nov. 3, 2009: Britain's Child Exploitation and Online Protection Centre launches a one-minute video message, produced in seven languages, that shows new images of how Madeleine might look.
August 2010: Kate and Gerry McCann meet with U.K. Home Secretary Theresa May for private talks.
July 28, 2011: A possible Madeleine sighting is reported in India, but the family spokesman downplays the possibility of it being a breakthrough in the case.
April 17, 2012: Spanish police search a Costa del Sol holiday resort after a tip from colleagues in Portugal.
April 24, 2012: British police who have been reviewing Madeline's case say their investigation is the first one to encompass information from all sources, and offers the "best opportunity" to solve the mystery. They also release a fresh age-enhanced image.
July 4, 2012: Scotland Yard says it has identified 38 persons of interest, including 12 Britons. Detectives say there is a chance Madeleine is still alive.
Feb. 6, 2013: A DNA sample from a girl in New Zealand is sent to British police. It does not match up with Madeleine's DNA profile.
October 2013: After shelving its inquiry in 2008, Portugal says it has enough new information to reopen the case.
Oct. 4, 2013: British police say they're looking at mobile phone data from the time Madeleine went missing, warning that anyone who was in the Algarve town on or around May 3, 2007, could receive a phone call from the Metropolitan Police.
Oct. 13, 2013: Speaking ahead of a BBC program on Madeleine, British detectives say details in the timeline of her disappearance were wrong. "The timeline we have now established has given new significance to sightings and movements of people in and around Praia da Luz at the time of Madeleine's disappearance," says senior investigating officer Detective Chief Inspector Andy Redwood.
Meanwhile, the number of persons of interest in the case is raised to 41, including 15 U.K. nationals, London's Metropolitan Police say.
Oct. 17, 2013: Scotland Yard reveals it has received more than 2,400 calls and emails after television appeals in the U.K., Holland and Germany. TV studios in those three countries got another 1,250 phone calls.
Jan. 13, 2014: Scotland Yard says it has three "prime suspects" — three burglars — who were believed to be close to the crime scene. British detectives say they believe Madeleine could have been abducted during a bungled burglary.
March 19, 2014: Metropolitan Police identify "a potential linked series of 12 crimes which occurred between 2004 and 2010 ... whereby a male intruder has gained access to mainly holiday villas occupied by U.K. families on holiday in the western Algarve." Police ask for help identifying the suspect so he can be charged and to see if he's linked to Madeleine's disappearance.