My Note 3 was stolen. How easy is it for the thieves to gain access?

[AC Question]

This Wednesday at a concert in Oslo my Samsung Note 3 was stolen from my pocket. After realizing this and looking around at the ground for it, i realized 4 others were doing the same thing. I borrowed a phone to call it only to find out it had been turned off or put in flight mode. A few minutes later while talking to the police, i was informed that this was a reoccurring thing at Slipknot concerts (the same guys stole over 200 phones while in Scotland)
A day later i read in the local paper that 2 thieves were caught with 33 phones combined. I had a little hope after seeing a picture of a Note 3 in the pictures published by the police.

Ahead of this i had blocked my sim, requested a remote wipe through google device manager and also tried to locate it with no success. IMEI number is also registered as stolen.
After talking with the police i was told they unfortunately did not have my phone among the 33 they confiscated.
I am now left to wonder how easy it would be for these professional thieves to gain access to the contents of my phone. Not counting the SIM, the phone itself has a 4-digit lock-code. It also has no SD-card, so all my pictures and data is in the phone storage.
There are also some pictures hidden in the gallery through the "hide media" function.
How easy would it be to gain access to this data? I assume the phone itself is halfway to Latvia already, but it is the contents of it i'm worried about.

Any answers would be much appreciated, both about the technical difficulty of gaining access to the phone and also about these thieves, should you have been unfortunate enough to have been robbed by them.
Have a nice day and thanks beforehand!

 

[Golfdriver97]

I think it would depend on the skill of whoever has the phone. It most likely is possible to pull up the data. But I guess a good counter question we will never know is what is the intent behind the theft? To sell on the black market? Probably. If that's all they won't care about the data.

As for what to do now, I think you have done all you can. A PIN is one of the better things to have in place...much better than a simple swipe to unlock. I would suggest in the future to place a security app on the device. My suggestion would be Cerberus. That one is really difficult to remove or bypass.