'Dexter's' bloody-minded expert

"It was just the whole idea behind being able to put pieces of a puzzle together to figure out what somebody did," she says. "It was pretty interesting to me."

As a student at Cal State Fullerton, Heale majored in criminal justice with a concentration in forensic technology, and for the past nine years, she's worked as a crime scene investigator for the sheriff's department, first in San Diego and then in Orange County. She doesn't carry a gun, and she's had her share of harrowing encounters with suspects at crime scenes.

But these days, her job has a lighter side too: She serves as a consultant on Showtime's Em- my-nominated series "Dexter." Lately, she's been reading scripts for accuracy, going on set for big investigation scenes and explaining DNA terms and technology to the cast and crew of the show, which is now in its third season.

Paper or plastic?: Whereas most procedurals portray evidence being stored in plastic bags, Heale suggested something different for "Dexter." "Plastic is a big no-no," she says. "With plastic, it will actually trap air inside. Over time, if it's not properly stored, there will be degradation done to the DNA where it starts to break down. Brown paper bags or Manila envelopes are the most common things that we'll use to collect and put our evidence in. And then if it's any type of bodily fluid on something, you definitely want to store that frozen. At the crime lab, we have huge freezers. If it's ever a murder trial, we have to keep that until the person's actually -- if they get the death penalty -- executed, or they die of natural causes. Because any time with the appeals, evidence may have to be looked at again."

Blood simple: Heale also advises on bloodstain interpretation. "There are different things that we look at that will actually allow us to determine and help reconstruct what occurred during the crime," she explains. "A swipe will be something where the blood was already put down, like it's already on the wall, and somebody walks by it and touches it. It's going to create a different pattern when someone actually has something on their hands and then touches a wall [creating a smear]. [With] high velocity impact, you can tell because of the type of pattern, what type of weapon was used. What we call arterial spurtings are commonly mistaken for high velocity. And that's basically when the jugular is injured, or someone is coughing, and they start spitting up blood. It can look pretty similar to velocity. So that's a little tricky at times."