Not sure if this is true but it seems crime in the US is on the increase after some years of decline.
Violent crime rises for second consecutive year
I know here in Australia there have been increases in crime rates but it is hard to gauge. They can get common crime down but then increases in drugs, gang organized related crime can go up.
Religion has been responsible for many wars and if you look closely, though they say it is in the name of religion there are other motives involved IE the IRA bombings have to do with British occupation from many years ago. But revenge attacks are often involved and this is more to do with mans hatred than anything else.
If some say that religion is declining and therefor the crime rate is declining well that is yet to be proved. But you also have to take into consideration effects that may not be reflected in the crime rates. Things such as divorce becoming easier and underage pregnancies have an effect on family breakdowns which can cause other problems.
I personally believe that as religious values are taken away then it is replaced with more secular acceptance of things. Moral values regarded as wrong. IE religion says you should not have affairs when married and you should only be faithful to the one you are going to marry. In secular society we have now watered that down so people have more casual relations and family breakdowns happen more often. From this we get a lot of unwanted pregnancies which lead to increased abortions. We also see an increase in sexually transmitted diseases and many people hurt emotionally. If you consider that many couples from the days gone by had long term marriages and stayed together more often now it is just about the norm for a marriage and family to break down quickly. Then this creates all the associated problems. Many people who have fallen into the crime statistics have come from a broken family.
The importance is taken away and even though society tries to say it is a persons right to do as they want with their bodies it allows other problems to come in and this can take a toll on a person and the society they live in. The young are becoming more promiscuous and they are not equipped to deal with these matters. So the effects may not lead to crime but they certainly have a cost factor.
You could also add to that list the holocaust and that was 6 million plus. All those killed in the 1st world war, and the 2nd world war and Vietnam war.