The IRS, at least, can. The IRS is specifically allowed to issue what's called a "levy" against a bank account without the need to go to court (there are other procedures that must be followed, but technically there's no warrant issued; it's a purely administrative rather than judicial process).
This may technically not qualify as a "seizure" of the account, since the levy amounts to, basically, a draft for a specific amount (as if the IRS was "writing a check" against your account), rather than the entire contents of the account. If you have more money in the account than the levy is for, the remainder will be untouched (except that banks are allowed to charge you fees for processing a levy).
Yes. It is usually referred to as 'plain view.'
The "catch" to this question is the word, "grave". This word is subject to interpretation. What is grave to some might not be grave to others.
Animal control can get a warrant to search and seize animals that are distress.
Almost impossible to answer without knowing much more detail.
Not without the approval of the court
To serve a warrant is to to read it, and seize the person against whom it is issued. To execute a warrant is essentially the same.
A Search Warrant
A general warrant, whereby and officer may be commanded to search suspected places without evidence of a fact committed, or to seize persons not names, or whose offense is not suppoted by evidence, are grievous and oppressive and ought not be granted.
No they can't. If they try to use it in court it would be immiscible.
yes of course they do
The fourth amendment of the Bill of Rights says that the government may not search or seize private property without probable cause. The Supreme Court has since defined regulations that law enforcement must follow in order to search and seize property. For example, the officer can obtain a warrant from a judge, if the officer sees the illegal property (In Plain Sight), or if the individual has already been arrested (Search Incident to Lawful Arrest). All of those cases would be considered probable cause for the government to search and seize property.
They obtain a warrant and confiscate it.