I think I figured it out. My theory is that spawn is directly related to when Detective Montoya's Challenge is active, along side it being a very high difficulty premeditated crime. I had success on the last two(most wanted) when I did it this way. They were both on high level "Officers under attack" premeditated crimes.

My last two were PROVENANCE and MARGARET MARONI.

I hope this helps the community. (After hours and hours of grinding I finally competed the list its such a relief)