I think maybe the Mayor is jumping the gun in Highland Park Mass Shooting

This year American's celebrated our independence with our three most iconic pastimes: parades, bar-b-ques, and mass shootings. 

In Highland Park Illinois, a gunman perched on a roof and started killing people as the parade moved down the man street. Six people were killed and "dozens" wounded but a single shooter. 

In Philadelphia, shootings hit 2 policemen and scattered hundreds during the fireworks display.

Any, I am intrigued by the mayor's comments in both places. 

The Philadelphia Mayor complained the legislature is held hostage by the gun lobby and are completely ineffective as a law making body. After saying how hard the job was with all the guns on the street, he also said he would be very happy when his term was over. You don't hear that a lot from elected officials.

Now the Highland Park Mayor's comments left me quite confused. She went on TV and said the shooter obtained the automatic rifle legally. She and the FBI also said they don't where the suspect obtained the weapon.

So here is my question, if we don't know where or how he got the gun, how do we know it was obtained legally? There might be a method in this madness, but I don't understand how it is possible. Someone is lying somewhere.