Dr. Maura Isles' (Sasha Alexander) father will be front and center in the upcoming episode of "Rizzoli & Isles" season 6.

In "Nice to Meet You, Dr. Isles," Cartermatt reports that the forensic expert's past will be resurrected due to an investigation regarding the death of a Boston jeweler. The dynamic duo's new case will lead them to a member of the Isles family, which the website points out to be the dad.

Apparently, Dr. Maura has been keeping a secret she does not want anyone else to know. Is her father capable of murder? Can someone as gentle as the good doctor be connected to a monster? So far, the viewers have not met any of her family. Is it because they are covering a dark past? And what will Jane's (Angie Harmon) reaction be once she finally becomes privy to her old friend's secret?

Last episode, viewers watched the duo uncover an unsettling murder. The body of a 16-year-old girl was found in a cage, with hair and blood all over her. Upon examination, Dr. Maura identified the samples as belonging to animals. She also found out that the killer was injecting his victim with drugs.

An acquaintance of Maura's, Dr. Foley, suddenly showed up at her office looking agitated. Bound by the doctor-patient confidentiality, he could not tell her that he knew who murdered the teenager. Jane pressured him into meeting her in the privacy of his office later in the day, but when she showed up for the briefing, he was already dead.

After keeping the clinic under surveillance, they nabbed a potential suspect. A teenager named Daniel was caught with blood all over his hands and shirt. But when they interrogated him about the two deaths, he played the innocent minor and claimed that Dr. Foley was the one molesting him. 

The police was then forced to play right into his hands. They set up his mother to lure Daniel to the precinct. Jane then pretended she left some paperwork upstairs and left the interrogation room. That was when the teenager tried to kill his own mom with a syringe full of drugs.

"Rizzoli & Isles" airs on Tuesdays at 9 p.m. EST on TNT.