The name of it was "Middletown Lanes" and it was located at 890 Washington St. It closed in 1994. It was a normal bowling alley but it was "sunken" (underground/basement) as in you had to go down a couple flights of stairs to go down into it. It was smoky, dingy, and no natural sunlight...it was a bowling alley. As far as it being scary, I guess that's open to interpretation. Where in CT was your mother from? There are lots of smaller towns surrounding Middletown that didn't have the "city" way of life, especially in the 1960's. Maybe that contributed to her experience? Like any city there were most definitely some questionable people, but that occurs anywhere. "Scariest place" though? I don't think so.

https://www.courant.com/news/connecticut/hc-xpm-1994-08-11-9408110521-story.html