i buy ipad second-hand it has icoud account i dont known the password

Unless we are talking about a device issued to employees of a business or institution, you will absolutely need this password to reactivate the device. The original owner will need to either give you the password; or alternatively, if they do not want to give it to you, they can go to www.icloud.com on a desktop or laptop computer, click Find My iPhone, and find the device name. After Find My iPhone decides that it cannot find the device, it will display a button to remove it from the account. They should press this button.

Your iPad is "Activation locked", described here:

Find My iPhone Activation Lock: Removing a device from a previous owner’s account

the previous owner must unlock it, or you will never be able to use the iPad.

contact the previous owner or return it for a refund.

I have the same issue.

Apple told me to take my iPad Mini to law enforcement. Taking
a lost iPhone or iPad to law enforcement is the stupidest thing I’ve heard. Apple
should have a system to be able to contact owners in regards of their devices.
I purchased an iPad mini from a second hand seller. (Not knowing they either
stole it or found it) It was working perfectly for a few months until I updated
it. Upon updating it locked up on me informing me that the iPad was lost and
gave me an iCloud owner message. I happen to be an honest person and tried to
return the iPad to its owner. The iCloud message gave me 2 numbers to contact. I’ve
called and on the first number was told I had the wrong number and on the
second I’ve yet to receive a message or call back. (I’ve tried contacting them
for a month now) My brother happens to be a Police Officer and I told him to
ask what would happen to the iPad if I took it in. He was told that they would
just leave it in evidence until someone claimed it. How in the world would that
“someone” know to go claim it? In my case I’m in Los Angeles and the numbers on
the iCloud message are one from San Francisco and the other is an international
number from Brazil. Apple would rather have the iPad sit in evidence forever
rather than come up with a better system to contacting their customers about
there devices. And please don’t ask your local Apple store for help cause they
look at you like you’re the weirdest person in the world for trying to return
an iPad to its rightful owner. Then they tell you there is nothing they can do
for you. ICloud lock the BEST and Stupidest Apple idea ever… At least come up
with a system to where if the so called owner can’t be contacted you (APPLE)
could erase the iPad at a local store and allow for the device to be used
instead of just letting become an expensive paper weight.

You obviously haven't bothered to read anything about how Activation Lock and Find My iPad works or you would know that users have the ability to send a message to the iPad - including contact information. To provide a default way to contact the owner is absurd. Giving a potential thief my email address, phone number, or other information that can potentially be traced to a physical address is the LAST thing I want. Especially if I happen to be out of town when I lose my iDevice.

Second turning in a lost or stolen device would allow the police to question the shop from where you bought it. They likely have a record of where it came from to protect themselves in just this situation. Even if the iPad does;t make it back to the original owner, at least the bad guys have a chance of being caught.

As for asking Apple, there is no guarantee they know who it belongs to. Even if last tied to a particular Apple ID, the user may have only used iTunes gift cards with no physical address. Do you ask your car dealer to find your stolen car? Do you expect Apple to go question the shop? Or worse, do you expect them to give you the contact information of a potential owner?

How in the world would that “someone” know to go claim it?

When a valuable item is lost or stolen you fill out a police report. if you find the lost/stolen item and you don't have a police report it's your word against theirs.

Lessons learned (hopefully):

1. Only deal with knowledgeable and trusted people you know, or
2. Buy a used device from Apple; they recondition them, and they have a warranty they will honor.

First let me say thank you for your response. I think I might not have been clear about what I was saying. In no way would I expect Apple to release any personal information what so ever. I’m not saying that the regular Joe should have access to that. That’s simply crazy talk. What I’m saying is that they (Apple) as a company should have a better tracking system if they are implementing iCloud security.

Don’t get me wrong I totally take responsibility for buying a second hand iPad. Especially from Craigslist. And trust me lesson learned in regards of doing that again. I was trying to save a few bucks and this is what I get for doing so.

I’m just frustrated at the fact that I’ve tried to get the device to its rightful owner by calling both phone numbers provided in the owner lock screen message. Like I said in my previous post on one number I was told I had wrong number and the other which happens to be a phone number in Brazil I have not had any luck. I’ve left voice mails and text messages.

So in my case I think taking it to the police is pointless (I might be wrong)

So at this point I’m stuck with an iPad I can no longer use. So even though I think it will never happen. This is where I was saying Apple could step in and just erase and bypass activation for those devices where you simply can’t find the owner.

DLandaPhoto wrote:

I’m just frustrated at the fact that I’ve tried to get the device to its rightful owner by calling both phone numbers provided in the owner lock screen message. Like I said in my previous post on one number I was told I had wrong number and the other which happens to be a phone number in Brazil I have not had any luck. I’ve left voice mails and text messages.

Only the rightful owner has the ability to provide that information on the locked screen. For some reason, this owner does not wish to be located.

What I’m saying is that they (Apple) as a company should have a better tracking system if they are implementing iCloud security.

No one does this today but Apple and because of that lead, the "kill switch" will soon become law in the US. Apple provides the tools, but I think it's nonsense to expect them to maintain some database to recover lost or stolen iDevices. Substitute any other product and realize how that sounds. It's not their business any more than it is the car dealer's job to find your stolen car.

So in my case I think taking it to the police is pointless (I might be wrong)

Yes, you have probably learned a lesson here, but your missing another point that I made earlier. You are still focusing on getting the iPad back to the original owner, but you're ignoring that you can help curb the problem of stolen iPads by providing the police with information to perhaps find the person who stole it in the first place.

This is where I was saying Apple could step in and just erase and bypass activation for those devices where you simply can’t find the owner.

Who should be the judge of whether you did everything possible to find the rightful owner? Apple? Imagine just how that would work and you'll realize how impractical that is. Why then should you benefit from someone else's bad luck?