Victorian police officers are now investigating what could have killed a young mother, who left a 15-month-old son alone in their apartment.

Here are the details, point-by-point, on the story of the toddler who survived a domestic tragedy alone:

-Police found the lifeless body of a 25-year-old woman while conducting a welfare check about 9pm Tuesday night at an apartment in Yarraville, Melbourne.

-The toddler was seen next to his mother's body. He was in his nappy and wearing pyjamas.

-Police noted the young mother may have died two days ago, but she had no signs of injury. She was found fully clothed in the lounge room, and the apartment looked "neat." Still, a crime scene was established as investigations continued.

-Rescuers noted the toddler was noticeably clingy after having been alone with his dead mum's body.

-The young boy was rushed to the Royal Children Hospital for treatment against severe dehydration. He has since been released from the hospital.

-Speaking to Herald Sun, Royal Children's Hospital spokeswoman Justine Nancarrow confirmed Wednesday the toddler had left their care "in a satisfactory condition."

-A neighbor who spoke to Sun said the woman may have been in the unit for a year. She reportedly moved from Tasmania. "She didn't have many visitors. She often walked past while I was out doing some gardening and we'd have a quick chat, mostly about kids. She was nice to talk to," he said.

Anyone who may have some information regarding the young mother's death may contact Crime Stoppers on 1800 333 000 or visit the agency's website at www.crimestoppers.com.au.