For Marcia Clark, it all started with Nancy Drew mysteries.I dont mean for this to sound frivolous, but I think it really might be that simple, the famous Los Angeles prosecutor-turned-mystery novelist says. I became a criminal lawyer, and then a writer, because of a lifelong fascination with crime and crime fiction.And that goes all the way back to being an avid fan of Nancy Drew when I was 5.Clark, who will be in Tarrant County next week for two events benefiting the Keller Public Library, became a household name nearly two decades ago as the lead prosecutor in the 1995 O.J. Simpson trial. But five years ago, she embarked on a different career.Now Clark uses her insiders knowledge, acquired through more than a decade with the L.A. District Attorneys Office and Special Trials Unit, in her work writing legal thrillers.Being a prosecutor was wonderful, she says. I loved it. I was happy to go to work every day. I felt I was doing something important. But I have to say, Im really, really not missing it, because I love what I do now even more. By becoming a novelist, Ive realized a childhood dream.Clarks three novels over the past three years chronicle the adventures of Special Trials Unit prosecutor Rachel Knight. The latest, Killer Ambition, was published in June by Mulholland Books, an imprint of Little, Brown. Shes currently working on book No. 4.Shell be in North Texas on Thursday for An Evening With Marcia Clark, a ticketed event that consists of dinner, remarks and a book signing. Itll be at 6 p.m. at Sky Creek Ranch Golf Club in Keller.She also has a free speaking engagement and signing scheduled at 3 p.m. Wednesday at the Keller Public Library.We chatted with Clark last week about her new life as a novelist. What compelled you to take the leap of faith and embark on a full-time writing career?It was something I always wanted to do. Although, I have to say, there was a lot of trial and error involved when I first sat down to write novels about five years ago. It took awhile before I felt I had gotten the characters right and the tone right.Now Im really glad no one can see those first couple of books. They found a resting place in the fireplace, and thats just where they belong. A lot of authors tell stories about shadowing real-life cops, lawyers and forensics types in the name of research. After your years of living in that world, how much of that kind of research, if any, do you need to do?I do have it easier, because I can draw on my experience. That means I dont have to prevail upon real cops and prosecutors for every little bit of information. Although I did consult with a computer expert regarding the hacking parts of the case in Killer Ambition, and with a crime lab expert regarding DNA. They were wonderful and generous with their time. But I wonder sometimes if they make themselves that available for everyone trying to do research. I imagine its not always the case. What do you most hope that readers take away from your books? Is it mostly about giving them a few days of an entertaining story? Or are you aiming for something more?I certainly want people to be entertained. But I also want them to be somewhat informed about the way investigations really work and about the way that cops and DAs work together: the camaraderie, the banter and the genuine sense of purpose, which is the heart and soul of law enforcement.These people really care. Theyre doing those jobs because they really care about others, they really care about taking care of victims, and they really care about justice. Its not just a job. Its a mission. When you do events like the one next week for the Keller library, do people still ask a lot of questions about the Simpson case? And if so, do you welcome those discussions, even though practically everything about the case has been asked and answered?Its interesting. Questions about that case are fewer and fewer. To the point that, in my last two speaking engagements, there was not one question about it. I think its because, as you put it, all the questions have been asked, all the answers have been given. Theres only so much you can say about it.Plus, other events have taken precedence since then. Other cases are in the news. So what I see more of is people asking me, What do you think of Casey Anthony? What do you think of Jodi Arias? What do you think of George Zimmerman?I suspect were more likely to get into some kind of discussion about those cases. Although mostly people just want me to weigh in in a kind of one-sentence, lightning-round way as opposed to having an extended discussion about it. Is it true that there might be a TV version of Rachel Knight in the making?Thats what were waiting to hear. TNT optioned the books for a one-hour drama series. We turned in the pilot script and were hoping to hear sometime soon if they want to shoot a pilot. How much of you is in the Rachel Knight character and how much of Rachel is in you?Well, Rachel is my middle name. Read into that what you will. For me, doing that made it easier to channel the prosecutor when I sat down to write. Not that I wanted to channel myself necessarily, but I think theres no way to avoid having myself in the character.Inevitably something in my own experience, something that Ive been through or seen or known, informs all of the characters I write and that means the bad guys as well as the good guys. Im all over the place in these books. Including the bad guys. Readers might want to re-examine the villains in your books to find evidence of your dark side.Uh-oh. I think I may have said too much!