you are also assuming that the federal government/USPS WANTS TO FIND who sent it... which might not be the caseIIRC, any package over 13 oz must be give directly to a clerk. It cannot be left in a mail drop or it will be returned to sender. The policy was implemented when I was working at the post office as a post master relief. Unless the regulation has changed, the bomber would have had to stand in line and personally hand the mail clerk the package.
What would happen if it was left in a mail drop and there was no return address?
or, as has happened, just enter it with a far larger mailing. good reason for maor mailers to vet their employees carefully.
That's what came to mind. Then there are security camaras in all the Post Offices, too? The postage cancelation marks name where and when.
How difficult should this be? There may be a picture of the perp, at the Post Office, if cameras there are any good. Other nearby cameras from surrounding business might catch the perp getting into a vehicle, if lucky. Widen the net from there. Bank cash machines, gas station vids, etc.
Attempted murder of law enforcement tends to seriously P.O. the po-leece, enough to make them go postal. [no offense]
you are also assuming that the federal government/USPS WANTS TO FIND who sent it... which might not be the caseA deadly ‘letter’ bomb that is less than 13 ounces can be made if you have access to the right stuff. Just stick it in the mailbox.