Earlier quoted context omitted.
The warrant does not imply that the coins were on an exchange. The warrant only indicates that they needed legal authority to seize coins, wherever they are. It seem more likely that the FBI/NSA had and gained some access to the gang's infrastructure and seized the money. Transmitting ransom money to an exchange without any type of tumbler or atomic swapping, that it's not a realistic scenario. Maybe they tried to us…
The warrant is for a location in Northern California and they needed a warrant to get it. Use your head man, this means they literally went to a Federal Judge and said "hey we have probable cause that this address is on Coinbase" and the Judge was like "wow that is pretty probable" and then they took the warrant to Coinbase who was like "oh damn that's legit ..... can we squirm out of dealing with this .... no ... oh…
Not neccessarily.
https://www.justice.gov/opa/press-release/file/1402056/downl...
The FBI in Northern California simply needed permission to use the Private Key they already had to access the bitcoin address.
The court that has jurisdiction over these types of crimes is in Northern California.