What happened
Diogo Alves was a 19th-century criminal in Lisbon who became associated with a series of robberies and killings and later acquired the nickname “Aqueduct Killer.”
The investigation
Historical court proceedings ultimately focused on murders committed during robberies. Later popular accounts attached additional crimes and dramatic stories to his name, some of which are difficult to verify from surviving records.
What the courts or investigators concluded
Alves was convicted of murder and executed in 1841.
Why the case remains significant
His story illustrates the difference between documented judicial history and crime legend: the conviction is historical fact, while some of the most repeated aqueduct stories grew through later retellings.
Case context
Crime by Region organizes cases geographically so readers can move from one file to other investigations from the same country. For unresolved or contested cases, the wording above reflects the distinction between confirmed events, investigative theories and findings actually established in court.