Authorities in the US have admitted they are baffled by the killing of a former White House military adviser found dead in a landfill site.

Detectives are trying to piece together what happened to defence consultant John "Jack" Wheeler.

His body was discovered among piles of rubbish at the dump in Wilmington, Delaware, on New Year's Eve.

Mr Wheeler, 66, served presidents Ronald Reagan, George Bush senior and George W Bush in a distinguished 45-year military career.

Police said they have no suspects and know of no physical or psychological illness Mr Wheeler had that would explain his disoriented state in video surveillance recordings from the days before his death.

Parking garage videos showed him in a black suit with no tie, wearing only one shoe even though there was snow outside. He was carrying his other ripped shoe.

He told a parking attendant he wanted to get warm before he paid for parking, but police said his car was not there.

He also said his briefcase was stolen and repeatedly said he was not drunk.

The last time he was seen alive on video, he was at an office building and had refused help from several people who approached him.

As a senior defence consultant and an expert in chemical and biological warfare, his death has fuelled numerous conspiracy theories.

Investigators said Mr Wheeler's death was a homicide but have refused to reveal more details about how he died.

Lieutenant Mark Farrall said: "We believe it was a homicide because it was ruled a homicide by the state medical examiners."

Police believe Mr Wheeler's body was in one of 10 rubbish skips emptied by a bin lorry on New Year's Eve and dumped at the landfill site.

Former homicide detective John Apeldorn said: "I think you could probably rule out a highway robbery.

"Somebody's going to rob you, they're not going to kill you and throw you in the dumpster. They're going to take what they want and get out of there."

In a statement, Mr Wheeler's widow Katherine said: "As you must appreciate, this is a tragic time for the family. We are grieving our loss.

"Please understand that the family has no further comment at this time. We trust that everyone will respect the family's privacy."

Neighbour Robert Dill said: "We are totally confused. At this point I couldn't even give you a theory."

Source - Yahoo.