Evidence depends on integrity of the process and of those who test it.

As problems continue to mount for HPD’s troubled crime lab, some are questioning if it is worth it.

"We have a problem. Somebody eventually is going to have to take notice, have to take a look at this and say you know what? We can't fix this,” said Brett Ligon an attorney who represents the Houston Patrol Officers Union.

The solution some say? Shut the DNA section of the crime lab down. 

Vanessa Nelson is the chief of the DNA/Serology Section of the HPD Crime Lab. She was brought here to renew the image of the troubled lab.

She’s now in trouble herself.

"If you are falsifying documentations on a simple test. How can you be trusted,” said J. Phillips, a former crime lab employee.

She said the testing allegations are only the beginning. She said it was all part of a pattern of deception; an attempt to discount the rules of the national accreditation board.

"She was willing to just throw that all away,” said Phillips.

The testing scandal? Well, that was Strike 1.

But Phillips alleges there was an attempt to tamper with evidence came next.

"This section manager also advised someone to recreate chain of evidence that was lost,” said Phillips.

That someone was her.

Evidence has to be handled in a very specific way, that’s called the chain of custody, and it is key to evidence being admissible in court.

If the chain is broken or tampered with, the evidence is worthless.

So, breaking that chain of custody was Strike 2.

Strike 3, said Phillips, was a suggestion to cover the trace evidence section with people not qualified, while it's qualified analysts were on vacation.

The American Society of Crime Lab Directors requires all analysts be properly trained in their specialty.

"When I said that ASCLD isn't going to like that. (Nelson) said, ‘Well ASCLD doesn't have to find out,’” alleged Phillips.

The crime lab society is also investigating the issues at HPD. That could impact the labs accreditation.

"If the lab were to ignore problems with the work of an individual or a technical problem then yes that could have implications,” a spokesman said.