Felipe Nerio Espinosa was a notorious Mexican-American murderer who killed an estimated thirty-two people in the Colorado Territory during the summer of 1863. He is widely considered to be one of America's first known serial killers.
There is no definitive reason as to why the Espinosa brothers began their bloody rampage but evidence suggests it was because the US Army had been tasked with arresting the pair over alleged robberies in the area. When the two men did not give themselves up, one of their homes was burned and their property confiscated. The pair had ended up in American territory after the signing of the Treaty of Guadalupe Hidalgo in February 1848. It had ceded the area and its Hispanic settlers to the United States following the conclusion of Mexican–American War. In the decade that had followed the treaty, many Hispanic people had lost title to their lands because territory courts showed an inclination to settle land disputes in favor of White settlers. Aided by his brother Vivian, Espinosa began his murder spree in the thinly populated area of what is now Fremont County, Colorado. "The brothers' first victim was found in May 1863, his corpse mutilated and the heart hacked out of his chest. During that summer, twenty-five more people were attacked and killed in similar fashion." During his reign of terror, Espinosa sent a letter to Territorial Governor John Evans stating his intention to murder 600 "gringos", including the governor himself, if he and the other members of his gang were not granted property and some 5000 acres in Conejos County where they once were. He demanded that Governor Evans give full pardons for himself and his followers, along with of land in Conejos County and appointments in the Colorado Volunteers. The letter also threatened that more Anglos, including the Governor himself, would be killed if the demands were not met. Lawmen, including Conejos County Sheriff Emmett Harding and Colorado Volunteer Commander S. B. Tappan, were dispatched to find Espinosa, but they met with little success. A posse out of Park County, Colorado finally managed to track the brothers southwest of Canon City, Colorado. Vivian was shot and killed in the ensuing gunfight but Felipe escaped. After hiding out for the remainder of the summer, Felipe recruited a fourteen-year-old nephew named Jose and resumed the rampage. Soon after, legendary tracker Tom Tobin was enlisted by the US Army find the pair. In a matter of days, Tobin found the outlaws' camp and in a brief gunfight shot and killed both Espinosas. He took their heads back to Fort Garland, Colorado.