Okay guys, lets please keep this calm. I don't care who came from where, as that's unrelated to the law. As far as we know, Empire may have an arsenal of his own, so it's inappropriate to accuse someone because of where they are from.
As for laws regarding the possession inside city parks, here's what I was able to find:
http://azstateparks.com/find/faq.html#q17
"
Q: Is carrying a firearm legal in Arizona State Parks?
A: Carrying a firearm inside any of our park's buildings is restricted (ARS 13-3102). Secondly, Arizona State Parks Rule R12-8-119 can restrict the carrying of a weapon outdoors. We do not ban legally carried firearms per se, but we have the right to limit exposure in order to maintain a family friendly recreational environment. Discharging of any weapon is prohibited."
http://www.tucsonnewsnow.com/Global/story.asp?S=13805896
"Under a new law passed last year and signed by Governor Jan Brewer, Tucson's prohibition on guns in parks is no longer valid."
Posted: Jan 07, 2011 5:16 PM
http://www.pima.gov/nrpr/geninfo/rules.htm#sec1090
"
1.090 Firearms
It shall be unlawful to discharge firearms or other weapons in Pima County public parks except in designated Rifle Ranges or Pistol Ranges. (Res. 2000-3, § 2, 2000)"
http://www.azleg.gov/FormatDocument.asp?inDoc=/const/2/26.htm
Article 2, Section 26 in the Arizona Constitution states:
"The right of the individual citizen to bear arms in defense of himself or the state shall not be impaired, but nothing in this section shall be construed as authorizing individuals or corporations to organize, maintain, or employ an armed body of men."
I am not a lawyer, so I am not at fault if one is arrested for breaking some unknown law, but it seems to be that State law dictates that A) Lawful citizens are allowed to carry firearms without restriction, and B) State law dictates that lawful firearm possession is allowed in PUBLIC parks.
Also, City ordinance 10869 repeals city code 21-3(5)(2), which means the possession of firearms inside city parks is now permissable.