"They could match extractor marks on the shell, yes."
If they don't have the gun and it's registered: Highly unlikely, unless it being registered they also get a spent shell casing with the extractor marks and firing pin indent on the firing cap. Also, if you don't "police" your brass, they have the shell casings at the scene, where there is likely a casing with your finger prints (loading the firearm) and possibly DNA (sweat or blood on the casing).
Realistically though, if it's a standard shotgun, smooth bore barrel, and you shoot rifled slugs or buckshot and leave no evidence of the shell casings behind, they would have a hard time matching it to just the projectile part of it.
Not really. They can match the gauge and spread pattern to distance from the target and barrel length, but nothing conclusive.
Yes, the police can trace a deleted account. The cyber security cell can trace older accounts too. They have advanced features to trace back accounts.
It can be done.
There is not a way to trace a call. Only the police officer can trace a call.
Usually the police can. But that would mean the people you called would have to call the police and ask them to trace the number.
Sometimes yes, but not always.
Yes.
Sometimes. The firing pin and extractor may leave marks on an ejected shell that can be matched to a gun.
no
I thinks so ??
File a police report.
Yes.