Alright, it's obvious that the officer did not follow the proper procedures here:

1) You DO NOT open a suspicious briefcase unless you know what you're doing
2) You DO NOT allow bystanders to surround you and look over your shoulder
3) You DO NOT try to diffuse a bomb without wearing protective gear

That being said, I guess it's a good thing that only the stupid officer died. It could have been worse. (less info)