Disclaimer: I do not own any part of CSI or its characters. That honor goes to the good folks over at CBS.

Spoilers: None. This also takes place before Sara left for Costa Rica.

Title: Mars

Summary: Seven dead women, one mysterious tattoo. Can Sara find and stop a serial killer?

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"So what did you find out at the hotel?" Greg asked his co-workers, pouring both Nick and Sara a mug of Boca Sunrise Coffee. "Anything that will help us nail this guy?"

"No," Sara pursed her lips, taking a sip of the citrus-flavored beverage. "Once we ID'd the body, we were able to locate her room. Although one of the hotel security officers said that she checked in with a male companion, we were unable to find any trace of a second person in her room."

Nick fingered the rim of his mug, staring into its murky depths. "And what's more is that the witnesses who saw her body fall to the ground did not see a second person on the balcony with her."

Sara stared at the far wall of the lounge for a moment, lost in thought. "I just don't understand what's going on here. Seven possible suicides, with no suicide notes or concrete evidence to prove that someone else was involved. It just doesn't add up."

Sitting down across from Nick and Sara, Greg took a swig of his coffee. "Have you had a chance to locate her family yet?" he wanted to know.

"We have," Nick confirmed with a small smile. "We were just about to go pay them a visit, actually. Caitlin Walker, age twenty-three, left behind both parents and a younger sister."

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"Caitlin's suicide came as a huge surprise to us," Wes told the two CSIs once everyone was situated in the family's living room. Holding his wife's hand in his lap, he closed his eyes for a moment in order to collect his thoughts. "Up until a few months ago, Caitlin seemed so happy. She was just about to graduate from college with a degree in teaching, and she was eager to begin working on her career."

Eileen sniffled, gripping her husband's hand with all of her might. "My baby was such a good girl. She never drank, she didn't do drugs, she had a 4.0 average. I just—why did she kill herself?" she asked Sara, her voice tinged with sorrow.

Sara briefly glanced at Nick, taking a deep breath to steady her nerves. Although she had never lost a child, she could certainly understand how distraught Caitlin's parents really were. "I'm so sorry for your loss, Ma'am," Sara began. "But you said that Caitlin seemed happy up until a few months ago, right? What happened to change that?"

Wes spoke up for his wife, his face turning crimson in fury. "It was her no-good, two-timing, drug addict boyfriend," he spit out. "She was a good girl until she met him. He destroyed her! He destroyed my daughter's life!"

This time it was Nick who tossed Sara a knowing look. "Sir, you said that this boyfriend made Caitlin unhappy, rather than happy?"

Wes nodded his head. "We never met him in person, but we could hear him over the phone whenever we called to talk to Caitlin. He was always putting her down, calling her worthless."

Eileen wiped several of her tears away, looking between both Nick and Sara. "Last month, she told us that she wanted to drop out of school."

"Did she give a reason, Ma'am?" Nick softly asked.

"Yeah, she said that she wanted to join the Mars Commune, and that she would never have to work outside of the compound again."

"The 'Mars Commune'?" Sara's mouth suddenly went dry. "Did she happen to tell you what the Mars Commune was?"

"No," Eileen started to sob. "She said that the commune was for members only, and that she would not be able to contact us again. We tried to find out where the place was located, but we couldn't. I just wanted to see my baby, to make sure that she was okay! I wanted her home with her real family, not locked away in some… some cult!"

"It's not a cult!" a voice shouted from just outside of the living room.

Sara's head swiveled in the direction of the voice, her eyes widening at what appeared to be a younger version of Caitlin Walker.

"It's not!" Sixteen year old Andrea Walker repeated, angrily staring at her parents. "Caitlin would have been fine if she had only followed the rules!" Shoving her hands deep within the pockets of her jeans, she tried not to make eye contact with any of the adults in the room. Speaking to non-members of the Mars Commune would get her exiled, and possibly even executed.

"Whoa, wait a minute," Nick got to his feet, surprise etched on his face. "You know something about this Mars Commune?" he asked her.

"Of course I do!" Andrea declared, fear now mixed with her defiance. "But I'm not going to tell you anything about it!"

"Oh yes you will, young lady," her father rocketed to his feet, completely caught off guard by the recent turn of events. "If you know what happened to your sister, you better start talking!"

"And who's going to make me? You?" she laughed, sorrow now also making an appearance on her face.

"No, me," Nick took out his cell phone in order to call Captain Brass.

"No, me," Sara corrected her partner, studying Andrea's expression. She could tell that she was enthralled by the Mars Commune, but she had also noticed Andrea's other emotions: the fear and sorrow had certainly not been lost on her. "Definitely me."

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TO BE CONTINUED