In the overhead shot of Jane and Maura at the start of the race they are right at the start line. Quick change to street level they are somewhere within the pack of runners.
A character refers to a legal case using the phrase "State of Massachusetts vs.". Massachusetts is a Commonwealth and legal cases are called "Commonwealth vs.".
At the end when Jane goes to arrest Jim Fillmore he claims that the statute of limitations the rape he committed had expired, to which Jane replies that since his victim was under the age of 16, and so still a child, the statute of limitations clock doesn't start until the victim turns 16. The Commonwealth of Massachusetts actually has no statute of limitations clock for the rape of a child under the age of 16.
At one point, Korsak refers to a recovered 9mm Hollowpoint bullet as an "assassin's bullet". In truth, the 9mm Hollowpoint is one of the most common rounds used today.
When Lieutenant Cavanaugh sees the rape victim he says she is his daughter's age. Most prominently in the series Lt Cavanaugh's family is mentioned as only being his wife and son who were killed. He does however have a teenage daughter, rarely mentioned, who he is not close to and was not married to her mother.
In the medical tent, when Dr. Isles (Sasha Alexander) is performing the impromptu autopsy of the first victim, she removes the bullet and shows it to Rizzoli (Angie Harmon). Rizzoli looks at the bullet and immediately proclaims it to be a 9mm. It is impossible to tell the difference between a 9mm, .380 ACP, .38, or a .357 without measuring the diameter with a micrometer and weighing the bullet. 9mm and .380 ACP bullets both have a true diameter of .355 inches and .38 and .357 Magnum bullets have a true diameter of .357 inches. That's only two one-thousandths of an inch difference, far too small a difference to be judged with the naked eye. Also, each of these bullet types come in a variety of bullet weights that can differ from a similarly weighted bullet in one the other calibers by mere tenths or even hundredths of a gram (i.e., 9mm 147 grain bullet at 9.5 grams vs. 148 grain .38 bullet at 9.6 grams). However, Rizzoli habitually makes educated guesses about details of her cases.
When Lieutenant Cavanaugh is talking to Vince Korsak, 1 on 1, he refers to him as Vince twice, but the third time calls him Rizzoli.
Correction: he says 'you and Rizzoli.'