One of the most vile and cruel acts ever performed by Muhammad was his bloody torture and murder of the men of Ukl or Uraynah. According to Muslims sources, some men converted to Islam and traveled to Medina. Because of the climate in Medina, these men got sick and Muhammad recommended that they drink camel urine and milk for their ailment. The Muslim sources claim that the men then apostatized, killed the herdsman and took off with the flock. Muhammad sent an expedition to catch them, and once they were caught Muhammad had them brutally tortured. Here is the version as narrated by al-Bukhari:
Narrated Anas bin Malik:
A group of eight men from the tribe of 'Ukil came to the Prophet and then they found the climate of Medina unsuitable for them. So, they said, "O Allah's Apostle! Provide us with some milk." Allah's Apostle said, "I recommend that you should join the herd of camels." So they went and drank the urine and the milk of the camels (as a medicine) till they became healthy and fat. Then they killed the shepherd and drove away the camels, and they became unbelievers after they were Muslims. When the Prophet was informed by a shouter for help, he sent some men in their pursuit, and before the sun rose high, they were brought, and he had their hands and feet cut off. Then he ordered for nails which were heated and passed over their eyes, and they were left in the Harra (i.e. rocky land in Medina). They asked for water, and nobody provided them with water till they died (Abu Qilaba, a sub-narrator said, "They committed murder and theft and fought against Allah and His Apostle, and spread evil in the land.") (Sahih al-Bukhari, Volume 4, Book 52, Number 261)