When Maura tells Jane that she might "move to Maine and write mystery novels", she is referring to Tess Gerritsen, the author of the novels on which "Rizzoli and Isles" is based.
On August 19, 2013 Lee Thompson Young failed to show up to the set of "Rizzoli and Isles." Police were called to do a wellness check on him at his apartment and found him dead.
In 4x07, "All for One," Angie Harmon had injured her ankle on set during shooting, so the injury had to be written in to the show, including in the next few episodes.
Most of the episode titles are song titles.
During the introductory scenes, Rizzoli's certificate as the Honor Recruit of her class at the Boston Police Academy is shown. "Lt. Procto Krapchek" is one of the signatories.