It is understood that the victim has claimed to gardai that a sexual encounter took place in the van, which was parked alongside the Crescent shopping complex in Limerick.
The Herald has learned that the teenage girl has provided officers with a detailed description of the alleged sexual assault after her parents were informed of the incident.
Officers are also satisfied they have identified the alleged assailant whom she met at the shopping centre before the incident. The victim is from Limerick city while the 17-year-old is also believed to be living there.
The alleged rape happened last week after she met the teen at the large shopping complex, which is an extremely popular hang out spot with teenagers.
Gardai are also examining mobile phone records in a bid to establish if there was prior contact between the two youths. It is understood that one theory being queried by gardai is if the pair met or communicated via Facebook before they met at the shopping complex.
It is believed that the girl befriended the teenage male and she willingly went with him to the van. Officers are satisfied that she did not suffer any violence prior to the incident in the vehicle on the afternoon of November 25.
Afterwards, it is suspected she confided in a teenage friend of what occurred inside the vehicle and her parents subsequently found out.
The young teen was brought to Roxboro Garda Station in Limerick by her parents and gardai were informed of her allegations. She was also treated at a sexual assault unit.
Gardai learnt of the incident more than 24 hours after it is said to have occurred.
The girl has since been interviewed -- in the company of an adult -- and provided officers with a detailed statement of her allegations.