'How to Get Away with Murder' season 3 air date, spoilers: Mahoney's killer revealed in premiere 'first minute'?

Fans have been waiting expectantly for the third season of ABC's hit drama series "How to Get Away with Murder," which will debut in a few months' time.
The series' lead star, Viola Davis, took to Facebook to announce the premiere date of "How to Get Away with Murder" season 3, which will be on Thursday, Sept. 22 at 10 p.m. EDT.
The announcement was accompanied by a photo showing Davis as the Middleton University professor, Annalise Keating, in scarlet. Keating is surrounded by her students, posing with blood-red splotches on their all-white clothes: Connor Walsh (Jack Falahee), Michaela Pratt (Aja Naomi King), Asher Millstone (Matt McGorry), Laurel Castillo (Karla Souza), and Wes Gibbins (Alfred Enoch).
Although news has been scarce regarding the cast, from the image posted, it can be safely assumed that the series regulars will be back for another slew of mystery and murder come season 3.
It is already known that Oliver Hampton (Conrad Ricamora) has been promoted to series regular starting this season. It follows that Walsh, whose acceptance letter from Stanford was intercepted by the former in season 2, is confirmed for the third season. Viewers may remember Hampton calling Stanford, impersonating Walsh, and telling its dean to never get in touch again.
"How to Get Away with Murder" fans may be wondering about Frank Delfino (Charlie Weber) after his exit last season when his betrayal of Keating was found out. Weber was quick to assure his fans that he will be returning for the upcoming run.
He told TVLine, "He just wants things to be OK with Annalise."
In the meantime, the showrunner, Peter Nowalk, earlier gave the series' patrons an idea of what they can expect from "HTGAWM" season 3. He admitted this newest run would take on a different format from the previous seasons.
In an interview with TVLine, Nowalk shared, "I like switching it up, honestly. I don't want the show to become stale."
Fans also asked about Wallace Mahoney's (Adam Arkin) murder in the season 2 finale. Whoever was responsible for it was not made known. Nowalk told Variety of the possibility that it would be revealed right off in the premiere episode.
"There are two options for me — it's either in the first minute in the show, or that's a longer mystery because it's a more complicated story."
More thrills then are coming up when "How to Get Away with Murder" returns for season 3.