It follows the discovery of a girl, believed to be under-18, in a house on Springfield Drive, Calne, shortly before 3.15pm on Friday. Despite the efforts of the ambulance service, the girl was pronounced dead at the scene.
Supt Conway Duncan said: “This investigation is still in its early stages but I would like to reassure the local community that a robust police response was launched yesterday and will continue in the days to come.
“People in Calne are likely to see a significant police presence in the area over the weekend as our enquiries progress.
“If anyone in the local area has any concerns, please approach one of the officers on patrol or at the cordon and they will be happy to answer your questions if appropriate to do so.”
Formal identification of the girl's body is yet to take place. Supt Duncan said: “The thoughts of everyone at Wiltshire Police are with the family of the victim at what must be a devastating time for them.
“They are receiving support from specially trained officers and we will continue to do everything we can to help them come to terms with what has happened."
The 17-year-old boy arrested by detectives remains in custody.