I'm a week late with this follow-up. (Sorry.)

Two weeks ago, I posted about an employee (fictionally named "Zoey") who had a peanut allergy. After she asked a peanut-butter-loving co-worker ("Addison") to be considerate, Zoey found a big glob of peanut butter smeared under her desk, which caused her to get sick. Addison denied being responsible.

To recap from last time:

*I said I would fire Addison if I determined that she did it out of meanness.

*I said I'd give a final warning to Addison if I determined the she did it as a "test" because she didn't believe Zoey really had a peanut allergy. (I also said that I thought it would be legal for an stricter employer to terminate Addison.)

*I said if Addison's workplace nemesis, Mildred, did it to get Addison in trouble, I'd fire Mildred.

*I said I'd fire Zoey if it turned out that Zoey herself did it, just to make a scene in the office and to get Addison in trouble.

What I did not say is how the employer should determine which of these things occurred. Or whether it was a complete accident -- for example, the night before the incident, a member of the company's cleaning crew took a dinner break and was eating his PB&J sandwich under Zoey's desk (his favorite spot) for privacy, got a glob of peanut butter on his hand, realized he had forgotten to pack a napkin that night, and wiped his hand off under Zoey's desk because it was less uncouth than licking the peanut butter off his hand and anyway he'll clean it up tomorrow night, having no idea that Zoey had a peanut allergy and might go into anaphylactic shock.

It could happen.

So, anyway, you are Zoey's and Addison's supervisor, and you don't know what happened, and Zoey is calling for Addison to be fired, and Addison is adamantly denying that she is the culprit, and Mildred is off to the side, smug and smirking, and the cleaning crew guy is whistling a happy tune and changing his vacuum cleaner bag before it's time to come to work, not suspecting that anything is wrong.

• Confirm that Zoey does have a severe peanut allergy. As I noted last time, there is reason to believe that her actual medical condition may not be as severe as she thinks it is because medical authorities say it is unusual for peanut butter "exposure" to cause an allergic reaction. Peanut butter consumption, yes. "Breathing" peanut butter, maybe not. Specifically ask her to have her doctor confirm that just being in the vicinity of peanut butter causes her to have these symptoms. What follows is based on the assumption that the doctor does confirm Zoey's condition.

• Get the details about the incident from Zoey -- time of day that she started feeling symptoms and discovered the glob under her desk. Since the office is small, ask her whether anyone would have been able to see what happened. Take names.

• Meet with Addison. Let her talk about the whole peanut butter controversy. How does she feel about it? Does she believe that peanut allergies are real? Is she skeptical of Zoey? Why? After you get a read on her general attitude about Zoey's peanut allergy, then ask for details of her whereabouts the day before and day of the "glob" incident. If she says she wasn't anywhere near Zoey's desk, ask her for names of employees or others who might be able to corroborate.

• Meet with all of the witnesses identified by Zoey and Addison, and follow up on any leads that the witnesses provide. Find out whether they saw anything unusual, but also ask whether they've ever heard discussions in the workplace about Zoey's peanut allergy. If they have, get as much detail as you can.

• I'm kind of joking about the cleaning guy, but I'm kind of not. Figure out who might have been in Zoey's cubicle besides her co-workers. Do you have a cleaning crew that comes in at night? How about repair people? IT people performing system maintenance after hours? If you can't determine whether a co-worker did it, you might want to talk to the contract workers and find out whether anything happened while they were there.

• I'm assuming a small office probably doesn't have any type of video surveillance cameras. But do check and make sure about that. If you have video cameras, you might be able to definitively determine who did it.

• Call a meeting of the employees. Explain to them that peanut allergies are real and that we have to be considerate of each other. Explain that "sabotaging" co-workers with substances that cause them to become physically ill is "harassment" under company policy as well as a rotten thing to do and will result in immediate termination of employment. Tell them that you will be monitoring the situation closely. Document the fact that you had this meeting and what you discussed.

• Be alert for any suspicious activity in Zoey's work area, like co-workers lingering there when she's not around, or - if you're really lucky - reaching under her desk when they don't think anyone is watching.

• Thank Zoey for coming forward and ask her to let you know if there are any other problems.

• Make sure that your work and cleaning crews know that you have an employee with a severe peanut allergy. If they eat while they're at work, make sure they don't eat peanut products in your suite.

• Consider defusing tensions by creating a nice "separated" eating area where co-workers may be able to eat what they want without causing Zoey any problems. In the warmer months, you may be able to set up an outdoor picnic table. Be open to other constructive suggestions from the co-workers and Zoey. Discourage employees from eating at their desks (that's an FLSA issue anyway), and do not let them eat peanut products at their desks.

• Consider moving a co-worker whom you and Zoey both trust close to Zoey's desk so that the co-worker can keep an eye on things when Zoey has to get up and move around. Do not appoint Addison or Mildred for this task.

Is all of this overkill? "Better safe than sorry" is more like it. Deliberately causing a person with allergies to get sick is arguably disability-based harassment that could get your company into legal trouble. (As if having employees send a co-worker to the hospital isn't enough of a concern in itself.)

BONUS: The above (without the peanuts) is a good protocol to follow if you ever find anonymous racial or sexually offensive graffiti in the workplace.