'Gibbs! Gibbs! Gibbs!'

Gibbs looked up as Abby bounced frantically towards him. He'd long since sent his team home. There was no mystery to solve, no killer to catch. The paperwork and loose ends about the obvious murder-suicide could wait; there was no need to work through the night on this one.

'Why haven't you gone home, Abbs?'

'Why haven't you?'

'Ah, you know me, Abby...'

'Yeah, you have no life and work late for no reason. I know. But I have a reason for being here...'

'Care to share? Or do I have to guess?'

'I was working on something for Agent Sato, on that crank call thing?'

Gibbs nodded. Someone had been leaving messages on Acting Director Vance's voicemail, in Morse code so there was no voice to ID, always traced, eventually, to a desk inside the building, and always sent at a time when the rightful occupant was nowhere nearby. Since the internal security cameras were undergoing a refit and there were huge gaps in the coverage, tracking down the culprit was proving more difficult than anyone expected, and Vance was going through toothpicks at a rate that had Gibbs seriously considering investing in company that made the things, trying to curb his impatience. Poor Chrissy Sato had drawn the short straw – literally – and gotten stuck trying to deal with the mess.

'Anyway, I was going through the footage on the cameras that are working... I didn't find anyone borrowing a phone they shouldn't have been using, but I did find... uh... this.'

She leaned over his desk and slotted a memory card into position. Her fingers flew over the keyboard – upside down, to his amazement. A few seconds later, the plasma screen sprang to life.

The slightly grainy black-and-white image clearly showed the team's area of the bullpen, deserted at the moment. Gibbs watched himself stride over to his desk, drop an empty coffee cup in the trash can, and retrieve a file folder before leaving again. A few seconds after his departure, Agent Jardine walked in from the direction of the elevators, glancing over her shoulder hesitantly. Watching, Gibbs's heart rate sped up. Apparently satisfied, she stepped over to Tony's desk, nudged his keyboard to one side, and pulled something out of her pocket. The angle of the camera didn't give them a clear shot of what happened next, but they did see her return the keyboard to its original position and reach towards her pocket again. Gibbs's stomach was churning as Abby paused the playback and zoomed in on Jardine's hand.

'That looks like a crumpled-up evidence bag to me, Gibbs...' she said, sounding apologetic.

'It is.'