Is there a safe untethered jailbreak for ios 6.1.3?

Hi, I've been scared upon reading comments of people where their phones don't turn on after trying to jailbreak it or their phone locking or something. I have an iPhone 4 and I was wondering if there's a safe untethered jailbreak for ios 6.1.3?

Everything is locked after 6.1.3 that is reputable. There aren't many at all that actually do work well that are compatible with this edition of software.

Just go to this website and get your free iphone 5 https://sites.google.com/site/azzinglegiveaways/

Http://www.alphajailbreak.com/
http://www.evasionjailbreak.com/
these sites will help you out.