There are at least seven artists that have used the name Killer:
1. A metal band from the United Kingdom
2. A metal band from Belgium
3. A rock band from Finland
4. A rock band from Switzerland
5. A punk band from Germany
6. A calypso musician from Trinidad
7. A death metal band from the United Kingdom

1) Killer were a NWOBHM band from Salisbury, England who later changed their name to Genghis Khan, and then again to Tokyo Blade.

2) Originally founded in 1980, the Belgian Heavy Metal Band, Killer, released 4 albums until 1990 when they ceased performing and recording.

3) Killer is a rock band founded in 1999 in Helsinki, Finland.

4) A band from Switzerland, whose best known work was the 1986 album "Young Blood"
(http://www.killermetal.ch/)

5) Killer is also a side-project from the german punk band EA80.

6) Killer was a calypso artist from Trinidad.

7) Killer are Death metal band based in Blackpool, England.