OSWEGO, Ill. -- A man armed with an AR-15 rifle helped stop a knife attack during an argument in Oswego.It happened on Monday at an apartment .on Harbor Drive.Police say it all began when someone with a knife attacked another person during an argument.Neighbor Dave Thomas, who witnessed the attack, went into his home, got his rifle and ordered the suspect to stop."I ran back into the home, into my house and grabbed my AR-15. Grabbed the AR-15 over my handgun. It's just a bigger gun. I think a little bit more than an intimidation factor definitely played a part in him actually stopping