23-year-old TerriLynn St. John vanished at around 7.30am on Tuesday morning as she prepared to take her three-year-old and one-year-old children to daycare.
When she didn't show up for work, her front door was discovered ajar by her parents, and the two toddlers were found unharmed but alone inside.
Police are now desperately searching for the US mother, but say it is 'too soon to tell' if she had been abducted.
'This is a missing person, under suspicious circumstances,' Middlesex Sheriff's Major Michael Sampson said as the search stretched into its second day.
Police also revealed they have interviewed four persons of interest relating to the disappearance.
'A person of interest could be acquaintances, whether they be personal acquaintances -- friends, family,' Major Sampson said.
'Miss St. John had a boyfriend at the time. He is obviously a person of interest.'
TerriLynn's boyfriend, Mac Kennard, told police that he last saw his girlfriend when he left her home at 4.20am to go to his work oystering.
Mac Kennard that he last saw Ms St John when he left her home at 4.20 a.m. before heading to work oystering. The pair can be seen in a series of Facebook shots kissing and smiling with TerryLynn's children.
TerriLynn's distressed father, Terry, said it appeared there were signs of a struggle when he arrived at the home and that someone may have been stalking her as she went to her car.
'They looked through the woods and you could definitely tell there has been a struggle beside my daughter's car,' he told local news crews.
'Jewellery was all around, like it had been broken off, her cell phone was found in the bushes.'
