On the first day of school there has already been a murder! There are four suspects and here is their stories:

The math teacher says he was giving a test to his students.

The librarian was sorting books.

The principal was giving a tour of the school.

And last, but not least, the janitor was cleaning up the bathroom.

Who is the Murderer?

  • $\begingroup$ You’ve gone to school or most of you have. So this answer should be clear $\endgroup$ Commented Nov 8, 2017 at 3:35
  • 1
    $\begingroup$ I think this needs to be clearer, it feels like there are too many answers. Who was the principal giving a tour to? If it was to all students, then how could the maths teacher be giving a test? Was the test to non-first yearers, and the tour was to first-yearers? The librarian and janitor both wouldnt have an alibi but the others would if their stories were true. I think this needs a bit more detail. $\endgroup$
    – Tas
    Commented Nov 8, 2017 at 5:17
  • $\begingroup$ It feels like this is a terrible play on another puzzle, where the maths teacher claims to be grading tests. Here, the teacher would've been alone and therefore have no alibi, and there would be no tests to grade. $\endgroup$
    – Tas
    Commented Nov 8, 2017 at 5:20
  • 2
    $\begingroup$ I like how it's phrased "there has already been a murder!" as if school murders are inevitable. And to add to a (large) list of possible solutions, the bathroom shouldn't have been used over the holidays. $\endgroup$
    – Alpha
    Commented Nov 8, 2017 at 6:01
  • $\begingroup$ Perhaps this puzzle has to do something with a collection of crows :-P $\endgroup$ Commented Nov 8, 2017 at 10:11

5 Answers 5


The murderer is:

The math teacher.


Because she SAYS she was giving a test to the students, which can be false. The rest of the statements should be true, because is not what they say, but are exactly what they did during the murder.

  • 1
    $\begingroup$ Good observation. ^ voted. $\endgroup$ Commented Nov 8, 2017 at 13:54
  • $\begingroup$ I mean, why is the math(s) teacher giving out a test on the first day of school? Perhaps it was a revision test (or pre-test, you might call it), but now we have to include an assumption ;) $\endgroup$
    – Mr Pie
    Commented Jul 21, 2018 at 9:45


The librarian


No-one has borrowed or returned any books, so the books don't need to be sorted.


Based on data given it could be

The maths teacher


On day one no tests are usually conducted.

  • $\begingroup$ What about a unit pre-test? $\endgroup$
    – boboquack
    Commented Nov 8, 2017 at 3:42
  • $\begingroup$ Well, 1st day is considered as day one of academic year. In such a case, perhaps there is no possibility of conducting any kind of test. $\endgroup$ Commented Nov 8, 2017 at 3:58
  • $\begingroup$ I have found in my experience that my teachers often start with an introductory test so they know where best to spend their time teaching. $\endgroup$
    – boboquack
    Commented Nov 8, 2017 at 4:01
  • $\begingroup$ math teacher will have the students as alibi. Why would the teacher take the risk knowing this? $\endgroup$
    – sona
    Commented Nov 8, 2017 at 10:02
  • $\begingroup$ Perhaps a determined murderer does not think prior to his/her actions... but definitely after! $\endgroup$ Commented Nov 8, 2017 at 12:19


My deductions are based on having an alibi

Math teacher would have an alibi of students. Principal would also have an alibi. The tour of the school also involves library. The librarian would also have an alibi.


I think

there is not enough information to determine who it is.

Why is the math teacher giving a test on the first day? It could be a pre-test, to determine what the students already know.
How about the librarian or the janitor? Why aren't the books already sorted, and the bathrooms already clean if it is only the first day? Perhaps there was summer school.
Why is the principal giving a tour? It's the first day.

It could be any of them, or none at all.


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