Yes. It is written in the Bible that Christians will be killed. But the truth is, Christians are the killers. Historically, a lot of blood has been shed in God's name. Men have enslaved other men and women in God's name. God's name is used to protect Christians with a sense that they are doing right when what they are doing is corrupt and wrong.
Do we need people in special forces, the police and the military? We do. But killing is always wrong whatever the reason and Jesus does not condone it.
“Ye have heard that it was said by them of old, ‘Thou shalt not kill,’ and ‘Whosoever shall kill shall be in danger of the judgment.’
Matthew Chapter 5:21.
A man or woman who is cop, when he or she believes in God and cultivates Christian values in their service and in their jobs, that will help them get back to God one day.
People who go for that kind of life know what they're getting into. If they're going in, then it's up to them to come out of it too. And only God can help them through that perilous journey. They're going in not for God, they're going because most of them like to hurt others and kill. Very few will hold the view of dispensing justice in service of those who are deprived of it.
As much as you would find many lawyers in hell, cops are no different. Not to generalize. Everyone of us will have our day in court while we are alive and we all use legal services somewhere during our lifetime or so many times during our life time.
None of us are perfect. This world isn't perfect. The way the system works isn't perfect. The aim then should be to bring as much change in all of this doing the best we can, in whatever field we are in and holding the principles and the life God wants us to live close to heart.
Those who question all this and stand for what is right and give their lives to bring about a change are the true heroes. Like MLK Jr, Malcolm X, Che Guevara. Their ways were not perfect either. But they strived for better lives for the people more than cops, lawyers and doctors ever have. Because we all work within the lines of the system, never once questioning why it is the way it is. Because that would mean trouble for ourselves.