At this point, we still don't who the killer or the victim is. In fact, just about everyone has a motive for killing someone, not just Jane, whom we saw in close enough proximity to the man who raped her and fathered her child that she might well have killed him, off camera at this point. The multiplicity of suspects makes Big Little Lies somewhat akin to a classic Agatha Christie story, except the suspects are suspect for different potential victims, and, again, we don't yet even know who the victim is.
Perry and Celeste, for example, could each easily be the killer of the other - Perry because he's a keg of violence on a short fuse, Celeste to defend herself against one of Perry's assaults. And, while we're on anger, Renata has plenty of it - justified insofar as her daughter is being bullied and bitten - but likely directed at the wrong person, Jane, which gives Renata a motive and again Jane in defense of herself or her boy.
Madeline and Ed seem to be most peaceful, but even they have the potential to murder. Ed is already suspicious that Madeline has been having an affair, and there's no telling what he might do if he sees and finds out more. And Madeline - well, in some ways, she's the most fascinating character on the show. Superficially, she's the most by-the-book and conventional of the women. But she has a wild side, and a propensity to express it, as whens she admits to grabbing Joseph's "ass" - prelude, in effect, to their car crash.
And the acting that animates this complex story is, as I said in my previous review, just all around superb. Reese Witherspoon, Nicole Kidman, and Shailene Woodley could and should each get Emmys for their performances, and Laura Dern, too, for supporting actress. And the men are putting in memorable performances, as well, with the less time they have on screen.
Speaking of less, my only regret, as I often say about these short series on HBO and elsewhere, is that they're short. Let's hope there's at very least a second season.
See also Big Little Lies: Big Good, Truly