A question about Jonathan

They say Jonathan was killed while drugging Dragon...

My question is, did Dragon kill him? Or did he die in some other way? (Mousetrap, etc)

I'm not sure if they ever specify, even in the book.

There is a pretty good indication in the book. When Mrs. Brisby first meets Justin, Mr. Ages asks Brutus if he remembers Jonathan. Brutus says "You mean the one Dragon..." before Justin cuts him off.

It's an interesting question though, because certainly on the movie side of things we're never given such a direct clue. We just assume Dragon did it, and the ferociousness he shows when attacking Mrs. Brisby and Jeremy helps convince us of that. Obviously Mrs. Brisby is convinced as well after reading Nicodemus' journal, the way she says "He was killed today while drugging the farmer's cat...Dragon..."

I think the problem is the only note we're given is "while drugging Dragon" which means it could have been anything.

But the hope I Found in Paul`s classic fan fic is that he was sent with some of the other rats on a mission to NIMH and was reported as dead to cover it up :?
That was very hard on Mrs Brisby .

I read one fanfiction a long time ago in which Jenner killed Jonathan when he came back through the hole in the floor.