Grissom was still sitting in the break room looking over a file when Catherine walked in. "Hey, Gris."

"Catherine," he acknowledged without looking up.

Catherine got a coffee cup out and poured herself a cup of coffee which appeared to be reasonably fresh and then sat down at the table with Grissom. "Anything interesting in there, Gil?"

Grissom looked up with a startled glance. "Oh, sorry, Catherine. I was just going over the coroner's report trying to see if there's anything we've missed."

"Mobley still on your back?" Catherine questioned sipping at her coffee.

"Like sands through the hour glass, so are the days of our lives." He responded coyly.

"I'll take that as a yes." Catherine took another sip. "So what do we know for sure?"

Grissom summarized, "Well our vic's throat was slashed so he couldn't call out for help, not that it would have mattered. He bled out and died within a few minutes. No defensive wounds either. So maybe he was asleep, or knew the killer."

"And nobody even noticed?" Catherine queried.

"Catherine, have you ever ridden the bus?" Grissom replied.

"No," Catherine looked at him with a quizzical expression. "That's why I have a car."

Grissom raised an eyebrow before continuing, "There is an entire subculture on public transportation. There is a unspoken code of conduct that people adhere to. People may sit next to each other every day, but rarely speak. Most people read or put headphones to shut everyone else out, some even nap. They like to sit in the same spot, day after day. If you don't ride the bus very often, you might shake things up by sitting in the wrong place. A bus is really a collection of people traveling alone." Grissom shared.

"Fascinating," Catherine said sarcastically. "So in other words, it is possible to commit murder in front of twenty-seven people, and have no one see anything?"

"Except our killer," Grissom smiled boyishly.