Police were initially called to conduct a welfare check on the 38-year-old Cowes woman at a property on Seagrove Way on 23 July.
The alarm was raised after Samantha failed to pick up her three children, two girls and a boy, from a local primary school.
Police attended the property just after 4.30pm and located her body inside the garage.
A post-mortem examination was subsequently conducted.
Based on the circumstances of her death, it is strongly believed to be suspicious and will now be investigated by detectives from the Homicide Squad.
Police are also investigating whether there was any interference with the crime scene.
Investigators have spoken to a 42-year old Paynesville man who was known to Samantha, however he was released without charge and enquiries are ongoing.
Detectives are keen to speak to anyone who may have been seen entering the Seagrove Way property on the day of Samantha’s death, or anyone who noticed any suspicious activity around her property over the previous days.
They have been told that she dropped her children off at school that morning and then had coffee with friends.
Samantha told her friends she had a midday appointment, however she failed to show up for this.
Police would particularly like to speak to anyone who can provide information on Samantha’s movements between 11am and 3.30pm that day.
They are also asking anyone who has dashcam footage taken on Monday, 23 July on Phillip Island to please download and secure the footage, then contact Crime Stoppers.
Investigators are particularly interested in footage taken in the vicinity of Seagrove Way, or between Seagrove Way and San Remo.
They would also like to hear from anyone with CCTV footage from Seagrove Way or surrounding streets on the day of Samantha’s death.
Anyone with information or with footage is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report at www.crimestoppersvic.com.au