Another set of intriguing cases challenge the Reagans on Friday, when “Blue Bloods” returns this week. The sixth installment of Season 7, titled “Whistleblowers,” focuses on Frank (Tom Selleck), who contends with a whistleblower’s serious claims that the NYPD is a hotbed of power abuse.

This may spell trouble for Frank, since he is accountable for everything that’s happening in the organisation. Other “Blue Bloods” cast members who will appear prominently on the upcoming episode include Erin (Bridget Moynahan), Danny (Donnie Wahlberg), Jamie (Will Estes), Henry (Len Cariou), Linda (Amy Carlson), Nicky (Sami Gayle), Det. Maria Baez (Marisa Ramirez) and Officer Eddie Janko (Vanessa Ray).

Spoiler alert! This update contains more "Blue Bloods" Season 7 spoilers. Read on at your own risk if you have not watched the latest episode.

According to TV Guide, Friday’s episode features Danny and Baez, who investigate a car accident, which they suspect is deliberately done. Meanwhile, Frank delves into an accusation made by a whistleblower, who says there’s been abuse of power within the organisation.

CBS has posted a sneak peek of the Oct. 28 episode of “Blue Bloods” on its official site. In the trailer, Danny sees a woman get hit by a car while crossing the street. He rushes to her and orders someone to call 911. The woman ends up dead, however, and Danny begins to investigate her case. Based on Danny’s conversation with the forensics expert, the woman took party drugs before the accident. Danny is amazed that the victim could still walk and talk despite her condition. The forensics expert, for her part, says that nobody parties that hard for a reason.

Danny finds a plastic bag of drugs in someone’s locker, which must belong to the suspect. He then interrogates a man, whom Danny suspects intentionally ran over the victim. Meanwhile, Frank wonders, “What is the right thing to do?”

“Whistleblowers” is directed by Eric Laneuville and written by Kevin Riley and Kevin Wade. SpoilerTV named other actors and actresses who will be seen in "Blue Bloods" Season 7 episode 5, such as recurring “Blue Bloods” cast members Abigail Hawk (Det. Abigail Baker), Gregory Jbara (Garrett Moore), Robert Clohessy (Lt. Sid Gormley), Tony Terraciano (Jack Reagan) and Andrew Terraciano (Sean Reagan).

The upcoming run will also feature additional guest stars including Delaney Williams (Dennis Egan), Miriam Hyman (Emile Cooper), Katherine Sigismund (Kathy Duncan), Kristin Parker (Rebecca Collins), Matthew Rauch (Lawrence Skolnick), Julyana Soelistyo (Dr. Amelia Sumardi), Patrick Collins (Jimmy Quinn), Jeannette Faye (Sinead), Robert Wuhl (Captain Ward Gibson), Zach Appelman (Sean Bartch), Richard Kline (Judge Angioli), Cynthia Mace (Siobhan Collins), Brock Harris (Derrick Sanders) and Jefferson White (Eric Carlson).

Find out what happens next on "Blue Bloods” Season 7, which airs in the US every Friday at 10 pm on CBS. In Australia, “Blue Bloods” airs on Thursdays, 10:30 pm on TEN.