Another Bert and Nan Tautm Mystery by Barbara Taylor Mcafferty and Beverly Taylor Herald is Double Exposure. I find myself reading this series out of order, which is something I prefer not to do, but I am reading the books in the order in which my library has secured them from other libraries for me. I am so greatful for this service.
The authors, Barbara and Beverly, are twins who write about twins. Characters, Bert and Nan Tatum, are mirror twins who were named after the Bobbsey twins. In this book one of the twins finds themself dating a suspected murderer, who is also an identical twin himself. The elderly lady who introduced him to her is found dead, murdered. Could she be next?