No.
Firstly, check out the format command in the online version of the comref so that you understand it correctly.
Secondly, the only way I can think of to get the name of the killer is to use an eventhandler. If you're not familiar with eventhandlers, check the comref, the FAQ and use the forum search function - there's a lot of good stuff on them kicking around. In this case you'd add the eventhandler "killed" (as I said above) to the hostage. The eventhandler is activated when the hostage is killed and it returns several things including the name of the killer.
You don't need to name the playable characters, they have names already. Name in this context does not refer to what you might call variable name: it refers to the actual name of the character, be in macguba, sergei lukin, david armstrong, TERA_Forrest or whatever.