The prisoner alleged that Murphy confessed to abducting Deirdre Jacob while he was serving a jail sentence for the brutal rape and abduction of another woman.
Sources close to the investigation said that Murphy has not yet been interviewed by detectives. But officers have spoken to the prisoner to whom he allegedly confessed.
However, gardai are understood to have received “significant” new information from other sources since they announced during the summer that they are treating the 18-year-old’s disappearance as murder.
Deirdre Jacob vanished in July 1998 outside Newbridge, Co Kildare. She had been on errands in the town and was seen by neighbours on her way home that afternoon before she seemed to disappear without trace.
The prisoner, who first came forward with the information seven years ago, was re-interviewed in recent months after Deirdre’s disappearance was upgraded to a murder inquiry. He claimed that a drunk Larry Murphy allegedly boasted while in prison of abducting a woman outside Newbridge.
After Murphy completed his sentence, the prisoner made several detailed statements about his alleged confession to retired detective Alan Bailey.
Bailey recounted in a subsequent book that the prisoner claimed that Murphy told him “he had pulled in alongside a young girl on the road just outside of Newbridge, waved the map in her direction, and asked for instructions on getting to a particular place.
“When the youngster leaned in through the open passenger window to try to see where he was pointing to, he is alleged to have grabbed her by her hair, and roughly dragged her down into the car, forcing her into the front passenger seat..”