I STARE INTO THE DRAWER. I'M LOOKING AT A SMALL-CALIBER handgun. O'Sullivan was killed with a small-caliber handgun. If this is the weapon, am I the best investigator in the world or the luckiest?

I take a pencil from the middle drawer and pick up the gun by lacing the pencil through the trigger guard. It's a .22-caliber minirevolver. A lady's gun.

What to do now? Call the cops?

How do I explain being here?

Leave it and risk Mrs. O'Sullivan getting rid of it at the first opportunity?

Leaving it isn't the best choice, but self-preservation is a strong motivator. I don't want to go to jail. On the other hand, if it's the murder weapon, I'm holding the only tangible link to the killer.

I look around the small, cramped room. There's no obvious place to hide the gun. Except-

There's a stack of manila envelopes on the floor. I take one and slide the gun inside. Then I shove the envelope under the pile of bulging scrapbooks and photo albums against the far wall. Not bad. I doubt even Mrs. O'Sullivan would notice the new addition to that mess.

Now what?

My watch says it's 3:40 p.m. Time to go. I back out through the door. I can't relock it. The fact that someone has come into this room will be evident the first time Mrs. O'Sullivan tries the door.

It's so quiet in the house, my nerves start to tingle. Now that I've done what I set out to do, with remarkable results, getting out should be the focus of my attention. The nagging thought that this was too easy, that I'm missing something even more important makes me pause at the top of the stairs to consider what I should do next.

Two possibilities present themselves. Check out O'Sullivan's office downstairs.

Or check out Jason's bedroom.

I turn back to the hallway. I close my eyes and let my senses "taste" the air. This morning, Jason smelled of Safeguard soap, Redken shampoo and CK One deodorant. I follow the same scent trail to the third door on the left at the end of the hall.

The door is not locked. When I step inside, I step into every teen's dream room. An LCD wide-screen TV hangs on the wall opposite the bed. A Bang & Olufsen system connects computer and TV and every conceivable music source imaginable. There's a desk and a small love seat. The desktop is clear except for the computer monitor. No bookcase. Nothing personal on the walls, only what looks like LeRoy Neiman sports prints. I recognize the collection because David has them, too. It's the Football Suite and when I look closer, I realize these are probably the original lithographs.

I move to the desk, open drawers, carefully shuffle contents although I have no idea what I'm looking for or why I think I should be looking here at all.

In the bottom right-hand drawer, under a stack of Play-boy magazines, I find an engraved envelope addressed to Jason's dad. I know as soon as I touch it that it's important-it's the old spidey sense again. The same kind of intuition that tells you to slow down because there's a cop up ahead or not answer the phone because there's someone you don't want to talk to on the other end.

I lift it from the drawer and open it.

An invitation.

From a pharmaceutical group in France.

Inviting Jason's dad to a press party introducing the world's first cure for HIV.

Is this why O'Sullivan dropped the Benton Pharmaceuticals deal? Did another company find a formula to rival the one they had been developing and beat them to production?

I'm staring at the invitation, trying to figure if this could fit into O'Sullivan's murder when the sound of a car door shatters my concentration and brings me back to the moment with a jolt.

Shit.

I peek out Jason's window. I'm two stories up, facing the back of the house. The front door is already opening, and I can hear Jason and his stepmother in heated conversation. I don't wait to try and determine what they're fighting about. I quietly shut Jason's door, take another quick look at the invitation, memorizing the company name, and slip it back where I found it. Then I open his window, climb out onto a narrow ledge under it and slide the window closed again moments before Jason trudges into his room.

He goes into his bathroom and slams the door.

With an eye on the ground, I leap off the ledge.