On or about February 4, 1896, two Mormon sheepherders were killed by an unknown assailant while they were camping along a creek in what was then part of Cassia County, Idaho.

He later became the partner of another rancher named Jasper Harrell and eventually they established a series of ranches on both sides of the Idaho–Nevada border.

Both of these factors prompted many cattlemen to begin building fences and establishing deadlines, a type of boundary which sheep were not permitted to cross.

He led many of the raids in northern Nevada and even poisoned water sources with salt, making them unusable for either faction.

Late in 1895, two Mormon sheepherders named Daniel Cummings and John Wilson crossed the deadline in Cassia County to graze their sheep in the Deep Creek Range.

When police investigated the crime scene, they found that only a small portion of the wood had been used for a campfire so it seemed as though the murderer arrived shortly after the delivery and made his attack that night, or early the next morning.

Diamondfield Jack was the prime suspect, mostly because in the past he had openly claimed he would kill the next sheepherders who crossed the deadline in Cassia County.

He was defended by James H. Hawley, a future Idaho senator, but was quickly sentenced to hang on June 4, 1897, due to the efforts of William Edgar Borah, an attorney appointed by the Elko County Sheepmen's Association.

He again escaped hanging when, on July 16, the Board of Pardons had Jack's sentence commuted to life in prison and he was sent back to Boise.

When he was finally released from prison in December 1902, Jack became a prospector and became wealthy digging for gold and establishing mining towns around Tonopah and Goldfield, Nevada.

[1][9][13][14][15] Today there are several markers in Nevada and Idaho associated with Diamondfield Jack or the murder case he was involved with.