How to say this?

I was watching an American drama talking about a serial killer. At some point they were talking the primary feature of his crimes - the victims tended to be older than the previous one. I understood this with the help of the subtitles in my language and failed to listen to what they actually said. I therefore how would native speakers normally say to describe that. Thank you.

There is a typo in my last posting, and I was asking how Americans would describe the crime features mentioned above. Thank you.

Let's look at this another way. Let's say that the first victim was Mr. Kellogg, age 20. The next one was Mr. Post- all of 25, and the third was Mr. Frank N. Berry was aged 30.

I suspect that the killer was that toothless wonder and sugar promoter, the Count of Chocula. I don't think that is royalty, even minor royalty.
My confidential source: Boo Berry

Since I am not Ted Bundy, that's about all I know on Cereal killers.

It was Dracula, not Chocula. I read that Chocula is now an Archduke. I wonder how he managed to rise so high in the world. It could be that he is healthier now, has less sugar, but the spokesvampire work is probably still tiring.

Modus operandi or MO. The way crimes are usually committed by a specific person. I think that's what you're looking for anyway.

"Each victim was older than the last" would be a common way of saying it.