Interesting how Springfield and its neighboring towns have always had their share of these cases. Many have been compiled by fellow sleuth Earth in this thread and is very comprehensive of missing (and a few related murders) Missouri women at the time:
MO - MO - Could These Abductions and Murders of Females Be Connected?
These particular cases listed below are narrowed down to similarities of victimology, location, time frame of disappearances (and murders), and manner of abduction (if known). This list does not include:
*Missing female children even though there are a few abducted not far from many of these, they appear to be a totally different M.O.
*Women that went missing in the 2000's.
*Women that went missing or were murdered from the Kansas City area. The Missouri River killer was operating at the time- although the victims were mainly prostitutes that were presumably not abducted and don't fit the victimology. (Many suspects including George Breeden, Terry Blair, and unknown).
***see last comment
*Also, I didn't mention the possibility of the I-70 killer's involvement in any of these cases as his trolling grounds were so broad- even though he's not ruled out as a possible suspect by any means.
***On a side note, I-70 highway runs straight through K.C. and St. Louis but for whatever reason it seems the I-70 killer was not attributed to any of those cases as far as I know. Many of the missing and murdered in K.C. and St. Louis at the time were affiliated with street life and prostitution.
A Serial Killer Murdered 3 Women in 1990 in St. Louis. He’s Never Been Caught
06/17/1985 - Jackie Johns from Nixa, MO about 15 miles from Springfield was last seen in a convenience store parking lot and her body was found in Lake Springfield. (Death attributed to Gerald Carnahan).
03/11/1987 - Diana Braungardt abducted from a parking lot in Festus, MO 200 miles (3 hours) from Springfield and never found. (No suspects)
08/02/1987 - Debbie L. Hall went missing from Carthage, MO, about 60 miles from Springfield. No info on her case.
01/19/1991 - Trudy Darby was abducted from a convenience store in Mack's Creek and murdered 60 miles from Springfield. (Jessie Rush and Marvin Chaney)
02/27/1991 - Cheryl Ann Kenney abducted from a convenience store in Nevada, MO 95 miles from Springfield and never found. (Jessie Rush and Marvin Chaney - suspects).
04/04/1991 - Angela Hammond was abducted from a parking lot and never found. (Jessie Rush and Marvin Chaney - suspects).
06/07/1992 - The Springfield three disappeared from a house and never found. (Robert Craig Cox - suspect among others)
08/23/1992 - Tammy Jo Zywicki's car broke down on 1-80 near LaSalle, IL and on September 1, 1992, she was found murdered along I-44 between Springfield and Joplin, Missouri. It was reported that a tractor/trailer was seen near her vehicle during this time period. (Clark Perry Baldwin was a suspect but as of a recent update, now he is considered not).
Tammy Zywicki Case: Accused Serial Killer Investigated in 1992 Slaying
Incidentally, Clark Perry Baldwin was an ex-Springfield, MO truck driver who was affiliated with similar murders out of state including:
Rhonda Knutson, 22, a truck stop convenience store clerk in northern Iowa who was bludgeoned to death during an overnight shift in 1992. Baldwin lived in nearby Nashua, Iowa.
Ex-Springfield, Mo. trucker charged in serial killings faces scrutiny across US
All these towns and cities are easily accessible off the interstates and not terribly far from each other. Trolling in these places late at night and then taking off in a fast getaway would be relatively easy.
Was this handyman with the green pick-up truck ever investigated thoroughly? Was his name ever revealed? Also I assume it was established that Jessie Rush and Marvin Chaney did not have access to a green pick-up? Were any of them tractor-trailer drivers?
Although these cases are similar, there are so many possible suspects.