Jesminder Bheeda's death and a mysterious stranger

I am playing a new save where my main sims are living in San Myshuno, in the old salt house. A strange thing happened, and an even stranger incident happened afterward. My male sim was by himself, and I was busy trying to get him to level up on some skills, when all of a sudden he goes outside and cries over a gravestone in the front yard. I panicked at first, thinking it was his girlfriend that died, but it turns out to be Jesminder Bheeda. I scanned and rescanned the notifications about her death, but there was nothing. It was just her sad gravestone sitting in the front yard, and there were no other mourners except for my sim. My best guess was it was seasons related? I'm in late winter in my game, just days before spring time - but there was no indication of how she died at all.

My sims are not acquainted with the Bheedas. In fact, I had to search what building they were living in. The best thing I thought I could do was have my sim take her urn to her apartment. From there, I switched to play her husband, Arun, so that he can take her urn. As he was mourning her, an NPC came out of the elevator, walked right into his apartment, and actually took care of the baby's needs (it was a girl named Celeste). She changed her diaper, bottle-fed her, and just held and talked to the baby. I quickly checked Arun's relationships, and this woman wasn't there. She was a complete stranger! Well, as I clicked him to introduce himself, she put the baby back in the crib and left the apartment without saying anything. How strange was that? ... Anyway, Jesminder's death and the strange occurrence in the apartment seems to be the most exciting thing that's happened in this save so far. I know that sims tend to barge into apartments anyway, but as she went directly to the baby and left hastily when Arun tried to talk to her, this mysterious NPC really had me intrigued (or maybe I just have an over-active imagination....I was thinking it was Jesminder's spirit in another sim's body, making sure her baby was ok!)

I might try and figure out a way to get Jesminder's ghost (another life form I haven't played with) and maybe I'll get some clues as to what happened to her. My sim who found her gravestone was 'training' up to enter the detective career....so it seems rather fitting that he has this mystery in his hands.