first, any account exclude very popular persons because have facebook protection!

first method:
you can easily close any facebook account, you only 2 infos.

- real name
- date of birth

but it is good when you know more personal things like the mail and the address.

create a new fb account with the same surname pretending to be the uncle/ant/mother/father.
than write the facebook customer service that your niece/nephew/kid with the targeting facebook account has died and there partner is using it.
send them a faked certificate of death with the name and birthday changed.

they will close the account as soon as possible and it will be very very hard for the person to reopen the account.

second method:

create a facebook account with the same name and write the customer service that the account and your e-mail account was hacked and you have no access to. say that you not logged in for couple of month because you where on a sailing turn or in africa or whatever.
they close the account for further account checking (they will ask for id).

when the victim send them the id, they reopen the account, but you wrote them that your mailaddress is hacked too.

in the moment they reopened the account write them another message that the hacker used your id from your send mails folder to make stuff under your identity!

it will be easier to reopen the account for the victim, but you can do it twice and on the second time it will be a pain in the ass for the victim!
i saw cases where facebook banned that person from their services!

the mothods work for more services like twitter ......