I am not sure who you mean by "both young ladies.".
In accounts of this case I've seen Bloomfield described as a suburb of Pittsburgh. It is not a suburb; it's a city neighborhood in the eastern part of the city. Mary Ann lived on Morewood Avenue, technically Bloomfield, I think, but on the border of the neighborhood known as Oakland, which houses the University of Pittsburgh and CMU. The Martinique Apartments are on Baum Blvd., which runs into the Oakland neighborhood at the edge of Bloomfield. Marcella Krulce, age 30, disappeared from that building without a trace. Her "hometown" was Canonsburg (also the hometown of Bobby Vinton and Perry Como) but she moved into the city because she worked downtown. From Bloomfield, it is a short bus ride into the "Golden Triangle," or downtown. In the early 1969s, it would have been a stretch to call Canonsburg a suburb, which is south of Pittsburgh. Even today, that would be at least a 45-minute ride on the interstate to downtown.
When I have time to get on my real computer, I will try to post a map that shows the Morewood Ave./Baum Blvd. area. The City of Pittsburgh is in Allegheny County. Beaver County is due west of Allegheny County.
Bloomfield itself is a traditionally Italian neighborhood, even today, anchored by a major hospital
and with a nice main street (Liberty Avenue) that includes Immaculate Conception Church and the school that Mary Ann attended.
ETA: Mary Ann's birthday is August 15. She would be 59.