In 1883, the Pima County Jail was located in the basement of the newly erected courts building. One commissioned head jailer along with three non-commissioned assistants were employed by Pima County Sheriff Robert Paul. While performing his duties on Sunday, May 4, 1883, Andrew W. Holbrook, Head Jailer, received complaints from several prisoners that breakfast had been distributed on dirty dishes. As Head Jailer Holbrook stepped into the jail yard to speak with an inmate dishwasher, he heard the door close behind him. He turned back towards the jail corridor to investigate. As Head Jailer Holbrook continued to his office, he was confronted by two prisoners, Joseph Casey and Henry Sinclair. Both prisoners were armed with pistols. Head Jailer Holbrook grabbed Joseph Casey’s hand and the gun discharged into the office door. As Andrew Holbrook attempted to return to the jail yard, Joseph Casey shot once more, wounding Head Jailer Holbrook in the back. The wounded jailer managed to retreat to the yard and hold the door closed, while yelling for help. His action kept the prisoners from escaping until help arrived to assist him. Andrew Holbrook died later that same day from his wounds.

On April 15, 1884, Joseph Casey was hanged by the neck until dead in the same jail yard where he had fatally wounded Head Jailer Holbrook. Henry Sinclair received a life sentence, which he served at the Yuma Territorial Prison. Andrew Holbrook was reported, by accounts of the time, to be a bachelor who was survived by one sister, residing in the state of Massachusetts.