GARDAÍ investigating the death of 13-year-old Cavan girl Jamie Maughan, who was missing for over a week, believe she may have been given drugs by an older person and then dumped at the vacant house where her remains were found.

The girl's family yesterday said that they believed she was murdered.

The body of Jamie Maughan, from Ard na Greine in Cavan town, was discovered about a mile and a half from her family home on Friday evening. She had been missing since last Sunday.

Forensic experts are conducting extra tests to determine whether she took any dangerous substances that may have led to her death, although sources said it looked increasingly less likely that her death was a suicide. Results from the initial post mortem carried out by the deputy state pathologist Dr Margaret Bolster failed to establish the cause of death.

Gardaí indicated yesterday that the results of these tests may not be available for a number of days.

Garda sources speculated that any subsequent investigation into the girl's death, if foul play is established, may be seriously hampered by the apparent delay in finding the body The family yesterday said they had concerns in relation to the garda investigation when Jamie was initially reported as a missing person early last week. However, it is understood that the girl had spent time away from home on previous occasions and had not contacted her family.

Garda sources said that she had been missing from home for a number of days as recently as two weeks ago and on that occasion had not contacted her family.

The family indicated yesterday that they would be considering making a formal complaint in relation to the investigation by the gardaí.

The girl's body was found fully clothed in the backyard of a vacant house in Harmony Heights estate on Friday.

Family members yesterday said that the body was in a bad state of decomposition and there appeared to be a number of bruises and marks consistent with a violent assault.