Within the next few hours...the blame will be on a Muslim or Muslims( most likely from Iran, Lebanon or Syria) claiming to be in a Extremist group or the typical "lone gunman" or "Sovereign Citizen".
What should be questioned is...the security. How did the so called devices get in these areas without anyone noticing them. How long have those backpacks there before the explosion. Since 9/11 Police Security has increased 10 fold for special events like this...so why was security so weak here?