Lines of communication were constantly harried by the guerrillas in a countryside that was perfect for ambushes, until it got to the point where it took two hundred men to escort a single dispatch. In 1811 Masséna would need 70,000 men merely to maintain safe communications between Madrid and France. All told, the Spanish and Portuguese guerrillas killed more Frenchmen than the British, Portuguese and Spanish regular armies combined, and also ensured that josefino civilians caught collaborating with the French, supplying them with information or food, faced summary execution. (As before, Britain stepped in quickly to help finance the opposition to Napoleon, giving various local juntas in Spain and Portugal an average of £2.65 million each year between 1808 and 1814.)
Once the French started responding to guerrilla terror tactics – which included mutilation (especially of the genitals), blinding, castration, crucifixions, nailing to doors, sawing in half, decapitation, burying alive, skinning alive, and so on – with almost equally vicious measures, the fighting in Spain swiftly took on a character that was a far cry from the warfare of élan, spirit de corps and gorgeous uniforms that had characterized Napoleon’s earlier campaigns, which for all their carnage had been generally free of deliberate torture and sadism. When Spanish banditti - men not in regular army uniform – were captured, they were hanged.
There was no logic to killing a uniformed regular soldier in battle and not hanging a bandit when captured.
Source:
Roberts, Andrew. "Iberia." Napoleon: A Life. New York: Penguin, 2014. 494. Print.
Original Source(s) Listed:
Tone, Fatal Knot p. 4, 182.
Sherwig, Guineas and Gunpowder pp. 367-8.
Blaze, Life in Napoleon’s Army pp. 58-9.
Further Reading:
Andrea Massena / André Masséna, 1st Duc de Rivoli, 1st Prince d'Essling
I was at a lecture about early days of Soviet Union. They did the same stuff, but had benefit of modern arms, like mustard gas. Sometimes they gassed entire forest, or slaughtered the villages they suspected were allied to rebels.