António Luís Costa and the Santa Comba Dão Murders
António Luís Costa, a former officer of Portugal’s Guarda Nacional Republicana, was convicted in 2007 of murdering three young women. Portugal’s Supreme Court rejected his appeal in 2008 and left the 25-year sentence in place.
Three disappearances
Between 2005 and 2006, three young women from the Santa Comba Dão area — Isabel Isidoro, Mariana Lourenço and Joana Oliveira — were killed. Their disappearances and the recovery of their bodies became linked during a Polícia Judiciária investigation.
António Luís Costa, a retired or reserve GNR corporal who lived in the same area and knew the victims and their families, emerged as the central suspect. He was arrested in June 2006.
Investigation and changing accounts
Contemporary Portuguese reporting states that Costa initially admitted responsibility during the investigation and provided information about where bodies had been left. He later withdrew or disputed those admissions and advanced allegations against another person. Those later claims became part of a separate calumnious-denunciation charge considered at trial.
The legal outcome therefore rests on the court judgments, not merely on an investigative confession. This distinction matters because Costa contested the prosecution case after his arrest.
The 2007 trial
The case went to trial at the Figueira da Foz court in 2007. On July 31, the court convicted Costa of three murders, including two qualified-homicide counts, as well as related offenses that included concealment of bodies, desecration of a body, attempted sexual coercion and aggravated calumnious denunciation. He was acquitted of one additional concealment count.
The individual penalties added up to more than the sentence Portugal could lawfully require him to serve. The court therefore imposed a combined term of 25 years’ imprisonment, the statutory maximum custodial term applicable in the case.
Appeals
Costa appealed. In June 2008, Portugal’s Supreme Court of Justice rejected the defense appeal and confirmed the judgment and 25-year sentence. Diário de Notícias also reported that the Supreme Court left intact the earlier appellate handling of the case.
Because the murder convictions survived Supreme Court review, this archive classifies the case as Solved / Adjudicated. The classification concerns the legal resolution of the three murders and does not endorse sensational labels beyond what is needed to identify the case.
The victims and the public record
The case became widely known in Portugal as the Santa Comba Dão serial-murder case. Crime by Region uses that description only as a factual shorthand for three separately identified victims whose murders were adjudicated together. Isabel Isidoro, Mariana Lourenço and Joana Oliveira remain the central human subjects of the record.