Fans are already excited for the upcoming midseason premiere of TNT's hit crime-busting series, "Rizzoli & Isles" Season 6 next month. And Detective Jane Rizzoli (Angie Harmon) and medical examiner Maura Isles (Sasha Alexander) will team-up again to face a series of tough challenges to solve the most complex cases in Boston.

When "Rizzoli & Isles" Season 6 ended in September, some questions were left unanswered, particularly regarding the mysterious kidnapping of Dr. Maura Isles. And while it was hinted Isles will survive the abduction ordeal alive, executive producer Jan Nash explained that Rizzoli will be struggling to solve the case, as previously reported.

"There's a mysterious element to it," Nash told TV Guide. "It takes a while to figure out what's going on. When they do figure out what's going on, it'll take a while to catch the perpetrator... We want to give her a meaningful nemesis in addition to these [standalone episodes]."

So, as "Rizzoli & Isles" Season 6 Episode 13 premieres on Feb. 16, here are 5 things fans would want to know on the second-half of the series.

1. Dr. Maura Isles' kidnapper

In the promo video for the series' upcoming episode, one of big questions was -- who kidnapped Isles? According to Crossmap, even though she usually holds the key in solving the crimes, she's never involved in any upfront activities like Rizzoli. But there might be some connection to a case handled by Rizzoli.

2. Jane Rizzoli might be in danger

In the previous episode, there's someone who is trying to frame Rizzoli. SpoilerTV hinted that the detective was aware that someone was "trying to hack" into her life. And the fire was also not an accident but was done by someone who's obviously after her.

3. The kidnapper could either be Isles' assistant Kent Drake or her biological dad Patrick "Paddy" Doyle, Jr.

Since Rizzoli and Drake are very confrontational, could his hate toward the detective led him to abduct Isles? But aside from Drake, her father Paddy, who's an Irish mob boss, can also be her possible perpetrator.

4. Why did Leanne need so much money before she overdosed?

According to a prison psychiatrist, Leanne had been trying her best to stay sober and vowed to never be back in jail. However, Design & Trend noted that she needed so much money badly, which would mean that she's trying to protect someone or might be doing the deed for someone.

5. The mysterious size 12 shoeprint

Before dying of cocaine overdose, Leanne was heard saying the words, "I won't let you down." And while there's no direct clue to indicate why Leanne would need so much money, things got even more interesting when the police found a size 12 shoeprint in her apartment. But it couldn't be her boyfriend since she broke up with Hobart in rehab. So, could the shoeprint belong to the kidnapper?

"Rizzoli & Isles" Season 6 Episode 13 airs on Tuesday, Feb. 16 at 9 p.m. on TNT. For the free online stream link, click here.