As police continue to search the area in Heidenheim where her body was found and follow up on more than 1,000 potential clues from the public, questions are being asked about how the kidnap turned to murder.

The Baden-Württemberg police must work out why the area of woodland where Bögerl’s body was found on Thursday evening had not been searched using dogs, even though her mobile phone had been found only a kilometre away.

Her body was only found by accident by the dog of a passerby. It had been there for a number of days, yet the police search teams failed to find it.

She had been stabbed to death and her body was covered with brushwood.

“One will have to look at which decisions were made and why,” a police statement said.

Bögerl, whose husband Thomas is the head of the Heidenheim Sparkasse bank, was kidnapped from the family home on May 12. Later that day he received a phone call in which the kidnapper demanded €300,000 and his wife told him she feared for her life.

An attempt to deliver the money that day failed – it was delivered at the agreed spot too late, police have now admitted, and was never collected.

“The tight deadline and very detailed instructions of the kidnapper prevented the ransom money being put at the intended handover spot on time. At 7 am the following morning the money had not been collected,” the statement said.

“The money handover was not optimal,” police sources have said.

The hunt for the kidnapper has also failed to deliver much so far, with analysis of his telephone call to demand the money leading detectives to say he is middle-aged and with a typical regional Swabian accent.

Police do not have solid evidence about whether he was working alone or with others. Even the search for a man with a ponytail who is being sought as a witness has not turned up anything helpful, despite several similar-looking men having been questioned.

The kidnapping has been decried as amateur by experts, who said a more professional operation would have waited for longer before making contact – and then have demanded more money.