Patrick Henry Sherrill (November 13, 1941 – August 20, 1986) was a United States Postal Service employee who, on August 20, 1986 in Edmond, Oklahoma, killed 14 employees with two .45 caliber pistols at his work place before turning one of the guns on himself and committing suicide. Six other employees were wounded. Security expert Gavin de Becker said that postal authorities ignored numerous signs of Sherrill's unstable and hostile attitude.
Sherrill was a relief carrier who would work routes on different days. He was making delivery errors and frequently delivered mail later than the customers were used to getting it. On the afternoon of Aug. 19, 1986, Sherrill was reprimanded by two supervisors in a glassed-in office. On the afternoon before the killings, he approached a female clerk who had been kind to him (while most people ignored him or hassled him) and asked her if she was coming to work the next day. She replied, "Of course." He told her she should stay home.
He began with one of the two supervisors who had spoken to him the previous day; the other supervisor had, for the first time ever, overslept and was an hour late to work, by which time the shootings were already underway. The second victim was Mike Rockne, grandson of Notre Dame football coach Knute Rockne. Fourteen people died during the attack, and six others were wounded. Some of the wounded survived because they played dead. The incident lasted between 15 and 20 minutes.