Factual error: When Mr. Sutphin finds Beverly's things on Richard Speck, there's an envelope he mailed her, with his return address, which is wrong. It is listed as Stateville Correctional Center (which is where Speck served his time in real life): Joliet, Illinois 60434. However, SCC is located in Crest Hill, Illinois 60403.
Factual error: When Dottie Hinkle is gardening, her garden boasts many different varieties of plants including iris, daffodil, and marigold. In Baltimore, where the movie takes place, these flowers bloom at different times during the spring and summer.