Iranian students holding the U.S. Embassy here gave visiting dipolmats a handwritten letter today said to be from Marine Sgt. Kevin Hermening, one of the hostages, to his parents, Mr. and Mrs. Ken Timm, of Oak Creek, Wis.

Timm, the Marine's step-father, said he was suspicious of the letter's authenticity and thought it "sounds like a bunch of baloney." This is the text of the letter:

We are still being held but are being treated very well. They are doing nothing to harm us at all. I think that the newspapers are not speaking truthfully back home nor elsewhere.

Just now I was interviewed by the leaders who are holding us and they had a paper which we could sign (if we wanted to) to ask the U.S. government to send shah back here in return for our release.

I did sign it, and am glad I did.

I'll explain most of my other fellings at a later time, I hope. We will not be set free until the shah is released and the longer we stay here like this the better there is a chance for something terrible to happen.

Just to let you all know everything here is O.K. I guess I was only downright, damned scared one time. Other than that I have been unbelievably calm.

We just lie around (hands and feet bound) all day and night and read books and magazines and eat three meals a day.

Maybe someone or something should tell (convince) Carter to take care of his American people first and not care about some stupid shah.

Then we could come home. Safe and alive.

I think I should go now, so I just wanted to tell you all, I love you very, very much and hope everthing turns out good.

I hope to write again soon . . . I will telephone the first opportunity I get. I love you all. Very much.

All my love, Kevin.

P.s. I was not forced to write anything I have written here. Just believe me.