They weren’t close. Family obligation was the sole reason why Sandra was present.

During the eulogy, Sandra couldn’t look at the casket—not because she did not want to see the stately container that held the remains of her older brother, but because the sunny glare from the surface of the black, polished casket irritated her retinas. Looking down at least gave others the impression that she was somber and grieving.

Seated five seats away was a man wearing sunglasses. Everything about him seemed fixed: His gaze on the speaker. His arms across his lap. His right leg hooked over his left. The locks of his sculpted dark hair rolling away from his part, as if it was a scene from the biblical Red Sea. Only his black necktie moved; it wobbled slightly from the anchor of the double Windsor knot due to the afternoon breeze.

Sandra leaned over and whispered, “Who is that guy?”

“Which guy?” Elizabeth whispered back. She was the elder of the two sisters, though both were younger than the deceased man.

“The guy with the long scar on his face.”

Elizabeth did not even turn her head to scan the audience for the matching face. “Oh, that guy? He’s Adam. He’s a close friend of mine from college; that’s how he met Thomas.”

The scar on Adam’s face seemed fixed, too: the irregular pale line, like a discarded piece of string, traveled from his left cheekbone down to the area near where his lips joined together. It was almost as if he had bitten a baited fish hook, only to have it rip across his cheek as he struggled for freedom.

“Oh,” Sandra replied, still tracing Adam’s scar with her eyes.

“I’ll introduce you to him at the reception,” Elizabeth murmured. “You’re going, right?”

“I think I’m going to go home first,” Sandra answered. “I’ll show up at your house probably half an hour after it starts.”

Sandra gently placed the casserole dish onto the table and hugged her sister.

“Thanks for coming,” Elizabeth said. “Mom and Dad are looking for you.”

“I saw them when I walked in,” Sandra replied. “But I haven’t seen Adam yet.”

“Yeah—he apparently had to catch a plane back home right after the funeral.”

“Oh.”

Three days later, Sandra murdered her sister.

Why?

UPDATE: The answer is below the jump.

Sandra murdered her sister to ensure the opportunity to meet Adam. Since he had gone to one funeral of one friend, it was likely that he would attend another. (The commenters were spot on.)