The incident is highly embarrassing for gardai who partly dug up the site at Lota near Glanmire in Cork two weeks ago, but had then left it unprotected. They had intended to resume digging when separate excavations at a nearby housing estate were completed.
Detectives yesterday visited the site, two miles from the city centre, to examine the hole left by the "grave robbers", just 20 feet from where gardai had excavated an 8ft by 6ft hole. Burnt plastic which may have covered a body was removed for forensic examination. A woman who rang a radio station on Tuesday reported seeing lights and men digging there the previous night.
Gardai are working on the assumption that the remains cannot have been moved far from the first grave in a 25-acre field.
The body is thought to be that of Denis O'Driscoll, 32, who disappeared last December. Police are now examining an overgrown pool which showed signs of having been recently disturbed. Unconfirmed reports said some human remains were found yesterday at Lota, including a fingernail, hair and part of a shirt.
The digging of the two sites followed a tip-off from a boy who reported seeing a man being battered to death. The child had suffered nightmares since the incident.
Cathal O'Brien, 23, from Wexford, and Kevin Ball, 42, a New Age traveller from Surrey, disappeared from their rented accommodation in Cork in April last year. They were part of the down and out community in the city. Mr O'Brien, a former computer science student, had been a volunteer at a local hostel for the homeless.
The fourth missing man, Frank "Blackie" McCarthy, reportedly fought with one of the two suspects after an argument. His family received an anonymous telephone call a month after he disappeared in February 1993 claiming that he was dead.