i must admit that after searching in the forums and some community sites, i was a bit surprised to see that there is no clear indication of what the ratio of people, evidence, suspects is for each mystery level.
For the Intermediate level, most sources indicate (6-7 ppl / 2 ev / 3 susp).
Some sources only give 7 ppl, but i had 6 too, so the 6-7 ppl indication seems correct.
I just had a 'favor' case (intermediate) where i found 7 ppl. 3 had valid alibies, 3 had NO aliby. I did not check the 4th, based on the assumption that there can be only 3 suspects at this level.
In the end, there was no PE matching any of my 3 suspects ! (yes, i was able to check them all)
Assuming only 2 possible evidence, which i found, the possible explanations I see:
1. the intermediate level can have 4 suspects. Note: a certain xls helper gives (6-7 ppl / 2 ev / 2-4 susp) 2-4 would be crazy, very little info from it.
2. the intermediate level favors deviate from the general (6-7/2/3) rule
3. it is possible for a killer to have no associated PE (?)
Thanks for any comments and a link to a good source of info ;)