Police

I will try to answer the first part of your question. I am not a policeman. But I have been through the academy and am duly licensed. However, I limit myself to putting out fires and investigating instances of arson when and where the occur. (I'm not sure about other states, but in Texas the Fire Department or the Fire Marshal's generally handle arson investigations rather than the police). Cop school was a lot more fun than fireman school.

Anyway, you need a reasonably clean record to be a police officer or a firefighter. But a few minor blemishes wouldn't necessarily hurt someone's chances. For example, I know quite a few officers and firefighters who have been hooked for MIP violations (Minor in Possession of Alcohol) in their youth. Considering they were applying five or six years after the incident, and could show they learned from their mistake, it didn't hurt them. Now, a person with 3-5 such run ins probably would not get the job.

In Texas, the rules actually say that you cannot have been convicted of a felony (no-brainer), a crime of domestic violence, an A Misdemeanor, or a B Misdemeanor within the past ten years. C Misdemeanors (traffic tickets, failure to appears, etc) are not disqualifying unless they are job related, or the department is picky.

Now, the specifics of your question are whether or not a person who has killed someone in self defense could get hired. I'll let Liam chime in with his answer, but my opinion is that it wouldn't necessarily prevent the person from getting the job. If they were not charged with a crime, and the rest of their background was solid, then they would probably be asked to explain the incident, but nothing more.

Generally, police departments and fire departments hire the same type people and have the following things in common:
1. no false information at any point in the application process
2. no history of illegal drug use other than the "experimental" use of pot in the past (3-5 years depending on the department)
3. stable credit
4. stable employment history
5. emotionally healthy
6. temperate in use of alcohol
7. good moral character (whatever that means)

Anyway, I hope this helps somewhat with your first question. But off the cuff, I would say that a self defense killing wouldn't necessarily disqualify someone unless it indicated an underlying problem of some sort.

Brady

On to your second question...

Homicide detectives are the cream of the crop, so to speak. That said, one thing to consider is that not every agency actually has detectives who specialize in homicide. Large cities will, but smaller places might have one or two who handle everything. Our department has four detective divisions.

1. Crimes Against Persons
2. Auto Crimes
3. Burglary/Forgery (lump in every property crime except vehicle related)
4. Narcotics/Vice

There are basically two kinds of detectives that I have known. The first is the crusty, battle hardened veteran who spent ten years in uniform before moving up. Recently, though, there has been a growing trend of younger, college educated detectives who might spend a year or two on patrol before switching to plain clothes.

Our guys spend a year on probation. After they serve one year of regular status, they can apply for a transfer to a specialized division. Rarely will a person without a degree get approved for transfer so quickly unless they are absolutely outstanding. Which of the four divisions they go to depends upon which they apply to and where the openings are. Most of them, however, start out in Narcotics. They can then move up from there.

As with everything else, education is the key. The more educated officer will move up more quickly, unless they piss someone off. The minimum educational requirements to be licensed are subpar for the most part. The last figures that came out said the Texas officers have on average 15 college hours. Someone with a degree is definitely on the fast track. (there are, however, a handful of Texas departments which actually require a Bachelor's Degree to even apply)

In other departments, promotion to detective status is based on a competitive exam. What I would suggest is that if your story is set in an actual city, look up their police department online and get a feel for what types of people they hire by checking their recruiting standards. Or, if it is set in a fictional area, look at a department that covers an area of similar size, etc, and do the same.

Every department does things a little different, so what I said above only applies to the guys and gals I am familiar with. But I have seen a growing trend in my area of younger folks acheiving detective rank quickly due to educational experience. They are simply more competitive than the average beat cop.

Brady

Glad I could be of some assistance. Feel free to PM me if you have any other questions. If you decide to set your story in an actual town in Texas, let me know and I can get some info on the particular department. Or if you chose to make up a town, if you let me know the approximate location, size, etc, I will let you know which department resembles it so that you can check out that department's info.

And I agree...keep all your options open! Good luck.

Brady H.