Police in New Mexico are now revealing the scope of the arsenal an 18-year-old high school student had in his possession when he opened fire during a May 15 rampage, killing three people. 

Beau Wilson, of Farmington, fired randomly in the neighborhood where he lived and discharged more than 190 rounds before police fatally shot him. 

On Thursday, the Farmington Police Department said Wilson carried three weapons in the attack, including an assault rifle. During the initial search of the residence he shared with his father, investigators found a backpack near the front door that contained 125 rounds of .223 ammunition for a rifle and 34 rounds of 9mm ammunition. 

Next to the backpack were two fully loaded 30-round magazines for .223 caliber firearms with the magazines coupled together with tape for efficient reloads, according to police. Further investigation by detectives revealed Wilson had acquired 220 rounds of .223 caliber ammunition two days before the shooting. 

NEW MEXICO POLICE RELEASE CRYPTIC NOTE FROM TEEN SHOOTER ACCUSED OF MURDERING 3 ELDERLY WOMEN, INJURING 2 COPS 

Farmington Police respond to residential area where Beau Wilson gunned down three women

Investigators work along a residential street following a deadly shooting Monday, May 15, 2023, in Farmington, New Mexico. Authorities said an 18-year-old opened fire in the northwestern New Mexico community, killing multiple people and injuring others, before law enforcement fatally shot the suspect. (AP Photo/Susan Montoya Bryan)

On the same day of that purchase, in a separate transaction, Wilson purchased three 30-round capacity magazines specifically designed for .223 caliber firearms, The Associated Press also reported, citing police. 

At a press conference in May, Farmington Police Chief Steve Hebbe said Wilson had been wearing what appeared to be a modified vest with steel plates, and that a note had been found in his pocket following the rampage. Handwritten in green lettering, the message said in part, "If your reading this im the end of the chapter [sic]." 

"Lay eyes or dear put a finger on my little sister I promis there will be regrets [sic]," the note added.  

NEW MEXICO TEEN WHO GUNNED DOWN 3 STRUGGLED AFTER LEAVING SPORTS TEAM: REPORT 

18-year-old Beau Wilson note

Farmington police released a note that officers found on 18-year-old Beau Wilson. (Farmington New Mexico Police)

At the onset of the rampage, police say Wilson fired at least 176 rounds from an AR-15 rifle just outside his home from the front porch area, but quickly dropped that weapon into some bushes, even though it still held more live ammunition. He continued firing with two pistols, discarding a .22-caliber gun and then depleting rounds from a 9-mm handgun in the final shootout with police, during which he let off at least 18 rounds, police said. 

Authorities said it appears that he shot indiscriminately at vehicles, and bullets struck 11 of them along with seven homes. Slain by the shooter were longtime Farmington residents Gwendolyn Schofield, 97, her 73-year-old daughter, Melody Ivie, and 79-year-old Shirley Voita, police said. 

Those wounded in the attack include Farmington police Sgt. Rachel Discenza and New Mexico State Police Officer Andreas Stamatiadas. The officers were treated at a local hospital and released. 

Beau Wilson's body and his body armor

Farmington Police released photos of Beau Wilson's body armor. (Farmington Police Department - New Mexico)

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Wilson reportedly struggled after having to leave his high school’s wrestling team. His mother has told NBC News he relied on the team for a sense of purpose as he dealt with his parents' divorce and falling behind in classes. 

Daxton Allison, one of Wilson’s former teammates, and former assistant wrestling coach Brent Stover told NBC News Wilson's exit from the team came as a result of a strained relationship with the head wrestling coach. 

Fox News’ Danielle Wallace and the Associated Press contributed to this report.