This has been mentioned a few times on the boards, but in case you hadn't read it, the Wake County DA (Colin Willoughby) will NOT take a case for prosecution UNTIL ALL the evidence is 'in,' meaning all testing done, including any forensics, but not only just forensics. He insists on everything being done, all 'i's' dotted and 't's' crossed. He proceeds very slowly and carefully (unlike Nifong, for instance). There's no statute of limitations for murder so he can wait to bring charges until he's got everything in, done, ready, and every little item on the to-do list is completed. He's known for this. It frustrates many people that he moves at a glacial pace. But as has also been discussed before, the DA only gets ONE SHOT to prosecute a case and this particular DA doesn't ever want to blow that shot; he is not a risk taker by any stretch. BTW, no arrest is going to be made UNTIL the DA's office is ready to proceed.
Now you can believe all the testing is back if you'd like; personally I think some of it is back and some is not since we're coming up on the 60-day mark and the crime lab turnaround is at a MINIMUM 60-days. Remember that putting together a criminal case is not only about forensics. And DNA isn't always found and therefore a murderer is not always tied forensically to his/her victim.
In the Laci Peterson murder case there was nothing in the house forensically that proved murder and there was ONE HAIR in Scott Peterson's boat, wrapped around a pair of pliers (it was Laci's hair). NOTHING else forensically was found in that case and yet Scott Peterson was not only convicted for first degree murder, he was sentenced to death. And COD was never established, nor was TOD, as Laci's body was too decomposed and missing parts, after 4 months in the SF Bay.
Evidence comes in many forms. It takes time to suss out all the different pieces of information and just because there isn't an immediate arrest and prosecution doesn't mean there never will be. If only life were as neatly wrapped up as an episode of CSI.