The brother of murder in the mansion killer Christopher Foster has called in a private detective to investigate the case.

The move comes as plans are finalised to knock down the remains of Osbaston House in Maesbrook, near Oswestry, which was set alight by the failed businessman who shot dead his wife Jill, 49, and daughter Kirstie, 15, before committing suicide.

The family have asked for permission to bury rubble they believe contains some of the remains of the schoolgirl during a short religious ceremony in a wood in the 16-acre grounds but have turned down the offer of a permanent memorial garden at the site.

They also want police to hand over a laptop 50-year-old Foster bought three days before the killings which they hope may hold important information about the pressures he faced immediately before the horror.

His brother Andrew, 46, said: “There are still a lot of things that do not add up and we owe it to Jill and Kirstie to get the truth.

“We cannot draw a line under these dreadful events and move on with the rest of our lives until we have done everything we can to tie up the loose ends.

“Chris owed substantially less than the £3 million mentioned at the time and so it seems even less likely that the debts made him act in that way. He was obviously under tremendous pressure and we want to know who was applying it, why and whether he was mentally ill. We owe it to Kirstie and Jill to get the truth.

“He was a good actor but I still cannot square the happy picture of the family at the barbecue with what he did hours later.”

Mr Foster said the remains of Osbaston House had become a magnet for ghouls with a video of the inside of the property appearing on YouTube.

Det Supt Jon Groves confirmed today: “We are in consultation with legal representatives of both the family and other interested parties in this case.

“The return of any property we retain is part of those discussions.”

By John Scott