Swiss returned to sender

[billsey]

So I believe I know that Pensionnat du Père Girard is a Catholic boarding school and that this letter made the rounds, it looks like to three different locales before being returned to the sender. Can anyone explain the markings and sequence for me?

[malolo]

Hi Bill,

Let's try this:

Fribourg 18 October 1917 to a member of the French Army in Briançon, Haut Alpes, France. Forwarded to Grenoble, which is crossed out in red ink and red ink on right side "inconnu" [unknown] - Retour a l'envoyeur [return to sender]

le destinataire n'a pu etre attein - "the recipient could not be reached"

There is probably additional information on the back such as receiving date stamps for its return to Switzerland and possibly transit date stamps for France. Since it's military within France maybe it stayed within the military postal system.

25 centimes international UPU letter.

[billsey]

Other side is blank, which surprised me a little. What about the pencil markings?

[malolo]

Difficult to read.

The red ink was typical for forwarding, blue and purple crayon [pencil] standard PO uses for lining out without obliterating writing. I only see "86" and a weird mark, and light pencil towards upper right. Can't tell what that is, but could be made on return to Convent. "86" could be room number at convent.