Emissary assassinated

[Gilrandir]

I would like to describe a strange accident that happened to me. I never had anything like that in all my years of playing MTW.
I was the Aragonese in high expert and within the first several turns I endeavored to bribe El Sid of Valencia (a four-star general at the beginning of a game is not a thing to disregard). So, I sent my emissary with a bribe offer and next turn I was informed that my emissary was murdered (it seems by El Sid personally as rebels cannot have assassins - or am I wrong?). Moreover, the cash that my emissary had on him was confiscated by El Sid. Well, there I was, bereft of my ambassador and virtually of all the starting money. I had to re-start the campaign.
Has anyone had something like that? Can someone else except assassins kill agents? How can the money be taken but the bribe turned down?