In the first day of a new class semester, a student was murdered inside the classroom. No witnesses, no murder weapon, and no evidence. The police got four teachers as possible suspects, but they all had alibis.

Their alibis were:

PE Teacher: I was in the GYM, checking and cleaning equipment.
English Teacher: I was in the library, looking for books.
Math Teacher: I was in my cubicle, computing students grades.
Science Teacher: I was in the laboratory, doing some experiments.

Who was the murderer? And why?

  • 8
    $\begingroup$ Is the capital GYM relevant for the puzzle? $\endgroup$ Jun 17, 2015 at 15:20
  • 6
    $\begingroup$ @Vixen You're meant to think it's the gym, but it's actually the Genuine Yoga Mall ;-) $\endgroup$ Jun 17, 2015 at 21:40
  • $\begingroup$ Why is it always the math(s) teacher?? ;D $\endgroup$
    – Mr Pie
    Jul 21, 2018 at 9:53

6 Answers 6


The murderer was

the maths teacher


it was the first day of semester, so he had no grades to compute.

  • 4
    $\begingroup$ You never know. There could have been a computer malfunction or fire caused by the science teacher that forced the math teacher to recompute student grades from past years. $\endgroup$
    – tfitzger
    Jun 17, 2015 at 16:01
  • 22
    $\begingroup$ I've had plenty of things graded in classes on the first day of the semester. $\endgroup$
    – Deacon
    Jun 17, 2015 at 16:05
  • 5
    $\begingroup$ And then there are the teachers who decide students' grades for the term based on their first impression... $\endgroup$ Jun 17, 2015 at 16:27
  • 3
    $\begingroup$ This would make more sense if the time of death was prior to the completion of the named murderer's first class. You could easily have a pop quiz in first hour and grade papers in second hour. $\endgroup$
    – ps2goat
    Jun 17, 2015 at 18:29
  • $\begingroup$ @user12365 Yeah, me too. But I'd seen this one before and knew what the intended answer was. $\endgroup$ Jun 17, 2015 at 21:37

A deeper (alternative) answer... [Don't take this answer too seriously]

It was all of them...
They killed the child's creativity and explorations with their strict policies to conform him to society! Reducing any form of expression to be forced into fitting their constraints. The child is no longer 'living' as free as he once was. His intellectual freedom has been murdered.
With this kind of murder, there are no weapons or evidence!

  • 7
    $\begingroup$ Lovely answer - I like it! $\endgroup$ Jun 17, 2015 at 21:41
  • $\begingroup$ @randal'thor , I did not see this entry, but I have added a "related" answer, for some Definition of "related". $\endgroup$
    – Prem
    Jun 19, 2015 at 18:29
  • $\begingroup$ I love this figurative answer. $\endgroup$
    – user88
    Oct 3, 2015 at 20:02

The Science Teacher. Science teachers don't perform experiments, they perform demonstrations and only to students.

It's also entirely possible for a math teacher to have assigned math work on the first day for students to complete in class and then be grading it later in the day. Or he was late in computing the grades from the previous semester.

  • $\begingroup$ Also the laboratory could be the classroom... $\endgroup$
    – George
    Jun 17, 2015 at 14:46
  • $\begingroup$ Computing grades is different from grading an assignment. $\endgroup$
    – Ryan B
    Jun 17, 2015 at 14:53
  • 2
    $\begingroup$ Good teachers will try things themselves prior to demonstrating to students. This ensures time is not wasted during the demonstration and helps the teacher when assisting students with the same experiment. $\endgroup$
    – ps2goat
    Jun 17, 2015 at 18:31
  • 1
    $\begingroup$ Again, that would not be an experiment. It would be practicing for a demo. The teacher is not mixing chemicals with unknown results or playing with lenses to determine new, unknown properties of chemistry or physics. They'd be rehearsing a known chemical or physical demonstration. It might be considered an experiment when the students do it because they don't know what will happen, but not when the teacher does it. At least not at anything short of a research university. $\endgroup$ Jun 17, 2015 at 19:30
  • 2
    $\begingroup$ Demonstrations done in science class are routinely called "experiments" by students, teachers, and textbooks. Yes, the word is not really an accurate description. But the fact that someone used an inaccurate term for something that he claimed to have done, given that everyone else in the building likely uses the same inaccurate term, is not evidence that he didn't really do it. $\endgroup$
    – Jay
    Jun 18, 2015 at 6:10

The murderer was...

The PE teacher! Because he said that he was cleaning equipment, although this is the duty of cleaning ladies. So he may was cleaning the... MURDERER WEAPON! dramatic music


It could be the

PE teacher.

It said there's no murder weapon, so

he could be cleaning up the mess and putting the equipment back together.


Murder on the Orient Express

Who was the murderer? All of them did it.
No witnesses, no murder weapons, and no evidence.
The Math teacher gave him an assignment to solve all the Millennium Problems within a day; and the students head hurt like hell.
The English teacher gave him an assignment to write all the works of William Shakespeare within a day; and the students fingers hurt like hell.
The Science teacher gave him an assignment to make a Huge Mars Rover Replica within a day; and the students hands hurt like hell.
The PE teacher told him to do 1000 pushups & lift 300 kgs & reduce his weight by 50% while doing all the other assignments; and the students body hurt like hell.
Then they all went on to their alibis.
The student went about with the assignments and, sure enough, collapsed within 30 minutes with fatal physical and mental trauma.
I repeat : No witnesses, no murder weapons, and no evidence.

Why? That is already answered above, but if you mean why they wanted to murder the student, then that was because they were teachers and they wanted to teach him a lesson about life (& unfortunately, about Death)

  • 3
    $\begingroup$ This answer must be accepted fast :p $\endgroup$ Jun 19, 2015 at 14:45
  • $\begingroup$ @SharadGautam , thank you for your support !! Nice to know that you liked this !! $\endgroup$
    – Prem
    Jun 19, 2015 at 15:38

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