Don Juan Murillo was a notorious Central American dictator whose ferocity earned him the nickname "the Tiger of San Pedro". After being overthrown around 1886 he fled to exile in Europe with a good portion of his wealth. Eventually he settled in England under the alias of "Henderson". He was a central character and the main villain of "The Adventure of Wisteria Lodge".
Don Juan was widely feared throughout Central America, considered to be the most bloodthirsty tyrant in any remotely civilised country. He was known to kill any man he considered capable of threatening his position. Some of his known victims include Víctor Durando, a diplomat to the United Kingdom, and García, a high-ranking minister. However, eventually a popular revolt forced him from power.
After leaving Central America with his children, secretary López and stolen wealth, Murillo travelled to Spain, landing in Barcelona in 1886. He then journeyed on to Madrid, Rome and then Paris before finally settling in England. He bought a Jacobean manor near the town of Oxshott in Surrey, where he lived with his children and secretary. Around this time he adopted the name "Henderson" to conceal his identity.
However, he was tracked by his former enemies, who desired revenge for the numerous crimes committed during his rule. One of these, Miss Burnet, an Englishwoman who had been married to Durando before his execution, managed to get a position as his governess. Together with Aloysius García, a member of a secret society dedicated to killing the dictator, the two planned to assassinate Murillo in his sleep. However, López realised Miss Burnet's true identity, and alerted his boss. Leaving Burnet under López's guard, Murillo went out and ambushed García, killing him. Murillo then kept Burnet locked in her room for several days, until she was rescued when Sherlock Holmes's investigation led him to suspect her as an accomplice in the crime. After she was freed, she revealed the truth of "Henderson's" identity.
Murillo and López, however, unfortunately escaped, and after reaching London left for the Continent, never again returning to England. Six months later both were found dead in a room of the Hotel Escorial in Madrid, having been living under assumed names as the "Marquess of Montalva" and "Señor Rulli". Inspector Baynes visited Sherlock Holmes to inform him of Murillo's death, who felt that justice, while belated, had at last come.