Familiar with dump site, most likely lives or works (or lived or worked) near the area where the bodies are found
May be dealing with more than 1 killer
Will have a history of violence against women , most likely sexually violent
Known to frequent prostitutes, therefore prostitutes should be interviewed in the area these girls frequented, to see if any of them had been assaulted before.
His vehicle will most likely be well maintained , but the mileage will reflect his constant forays out to pick up women (high mileage)
*Investigative consideration: In some areas there are what are called "bad date" Sheets (Project SAFE etc..)which are lists where sex workers voluntarily submit reports of bad encounters they have with Johns, give personal and vehicle descriptions, as well as where and what happened and what the "date" entailed, and what the John stated verbally before and during.
Look for any reports of John's who assaulted victims primarily any who attempted to strangle women, and any repeatedly matching descriptions of such individuals.
This offender is extremely comfortable in the area the bodies were found, it takes time to dig a grave and bury an adult, yet to do it multiple times in the same area, on what appears to be just on the outskirts of town
Victimology:
Victims are all prostitutes, which severely elevates their risk of encounter, due primarily to lifestyle , which is highest amongst prostitutes who are working the streets, slightly lower amongst "Call girls" and Escorts
To the offender they are extremely low risk , which tells us a few things about our offender
Low level of sophistication, chooses "easy" victims, MO may be nothing more than agreeing to a date or flashing money.
May produce a weapon initially to force victim compliance , this may include driving the victims to where their bodies were found , then assaulting and killing the victims there where he has an established level of comfort . Most if not all victims were strangled, which also gives some insight into the offender personality, hes "hands on"
At the outset of his crimes there was most likely a triggering event that started everything off (legal, money intimate etc.)
Assaults(murders) most likely take place in or near the suspects vehicle once he has a victim, therefore he may have taken precautions , IE disabled door locks and or windows , however a secondary crime scene (residence etc..) cant be ruled out , but I feel its unlikely
Motive: Could be a number of motivational factors , primarily anger
Why did he stop (or did he ?) , could be one of many things
-Dead
-In prison
-Physically or mentally incapable
-Operating in another area
-Its also possible (though rare) he no longer had the urge to continue, as sometimes they do stop.
One more thing , hes most likely known to LE already