A theft deterrent device includes a carrier having a pivotally mounted pin and an alarm tag for receiving the pin to secure the carrier and alarm tag together when secured on an item of merchandise by an adhesive pad on the carrier. Spaced electrical contacts within the alarm tag receive the pin therebetween to complete an electrical path to close an electrical circuit which turns the device on. The security device is configured to sound an onboard alarm in response to prying of the carrier from the alarm tag or cutting of the pin of the carrier, or if an EAS tag receives a wireless signal from a security gate. The carrier remains on the purchased merchandise for subsequent disposal after removal of the alarm tag from the carrier by the use of a magnetic key to unlock a locking mechanism which engages the pin.