Now, what makes this interesting is that, at least in the US, when a prosecuter charges, say, a serial killer, he's generally going to try and pin every last body that turns up on the defendant.
Not true. In the Atlanta Child Murders Cases they prosecuted Wayne Williams with only three out of 20+ of the murders even though they had strong evidense to tie him to many many more than that.
Yes true. Leaving aside that this is largely extraneous to the point, Williams was the exception, not the rule.
John Wayne Gacy - charged and convicted of 33 murders, although only 28 bodies were actually recovered.
Ted Bundy was tried no less than 3 times in different jurisdictions, receiving a total of 3 different death sentences.
Jeffrey Dahmer - 17 bodies, 17 (reduced to 15) charges, 15 convictions.
Lots of info on serial killers on
Wikipedia