David J. Cook was born August 12, 1840, in Laporte county, Ind., being a son of George Cook, a farmer and land speculator. Receiving a moderate education, he worked on farms in Indiana, Iowa and Kansas until 1859. His father settled in Iowa in 1853, on the present site of Laporte, now a thriving city, but then a howling wilderness. Selling out to good advantage, the family moved to Jefferson county, Kan., in 1855, settling on a tract of land north of where the little city of Meriden now stands, on Rock creek. When the wave of excitement which swept the country on the discovery of gold at Pike's peak came, it bore him to the Rocky mountains, where he spent nearly two years in mining in what is now called Gilpin county, Colorado. Returning to Kansas he bought a farm, but in the fall of 1861 he went to Rolla, Mo., and engaged in running supply trains.
He was soon afterward transferred to the ordnance department of the Army of the Frontier, and early in 1863 came again to Colorado and established the association with which his name has since been connected, and which has so long been a terror to evil doers and a trusty guardian of the public safety.
Enlisting in the Colorado cavalry, he was in the spring of 1864 detailed by the quartermaster of the Denver post as government detective in Colorado, and served until the abandonment of the post in 1866. He next served three years as city marshal of Denver, and in the fall of 1869, was elected sheriff of Arapahoe county. So satisfactory to the people of the county, of both political parties, was his administration of the sheriff's office, that at the end of his term he was reëlected without opposition, and served two years longer. From 1873 he gave his entire attention to the detective work, holding at the same time the position of deputy United States marshal until the fall of 1875, when he was again elected sheriff, and reëlected at the end of two years, his last term expiring in January, 1880. In 1873 he was appointed by Gov. Elbert, and confirmed by the senate, major general of Colorado militia; was reappointed by Gov. Routt, and again by Gov. Pitkin, serving four years under each. He has served as major general for nine years, and has rendered efficient service in quelling riots throughout the state, as well as in recent Indian troubles. During the Leadville strike, which occurred in June, 1880, and in which Mooney was to that city what Dennis Kearney has been to San Francisco, Gen. Cook was sent by Gov. Pitkin as commander-in-chief of the state militia, and by his efficiency soon brought the rioters under subjection to the laws of the state. During what was known as the Chinese riot, which caused such disgrace to Denver on October 31, 1880, the mayor and sheriff called on Gen. Cook to quell the riot, after the authorities had failed to do so. Gen. Cook took charge of the police and twenty-five special police, nearly all of whom were trusted members of the Rocky Mountain Detective Association, that he swore into service, and in a short time brought the rioters under subjection and caused them to disperse, after arresting the ringleaders and placing them in jail. The resignation of Mr. Hickey as chief of police caused a vacancy which the leading business men of Denver thought Gen. Cook the most fitting man to fill. Knowing the great desire manifested in regard to having an efficient chief of police, the city council confirmed Gen. Cook in that position.