THE police team, who conducted the painstaking investigation into the Geen case, had never experienced a criminal inquiry quite like it.

Up to 40 officers collected evidence by speaking to witnesses, potential victims, hospital staff and relatives, medical experts, anaesthetists and toxicologists.

After they were called in to Banbury's Horton Hospital, police had to examine the evidence surrounding 27 patients, eventually narrowing the case down to the 18 which relate to the charges Geen denied.

Det Supt Andrew Taylor said: "While Benjamin Geen featured in our investigations, the inquiry was wider than that.

"We had to establish whether there was an inexplicable respiratory arrest, then who was responsible.

"A picture emerged of a young man who wanted to be the centre of attention. He revelled in the attention of being in the thick of things. He seemed to be narcissistic.

"Thames Valley Police has previously investigated cases within a health care environment and nationally there have been a couple of notorious ones, but I don't think anyone involved with our investigation had ever experienced anything like this."

Det Chief Insp Pete Bierne, also involved in the inquiry, said: "It was not only about being the centre of attention, he liked the action.

"He wanted to be involved in emergencies, bringing people back from the dead. The majority of them had stopped breathing and if you stop breathing for more than two to three minutes you are dead."

Det Supt Taylor said it was when one of Geen's victims, Timothy Stubbs, 41, stopped breathing, the penny dropped at the Horton.

He said: "They decided the number of respiratory arrests occurring couldn't be explained and needed investigation. The hospital did a review and at that point they decided to tell us of their concerns.

"There was a group of eight cases which gave them cause for concern.

"For us it was something new, it was potentially a large investigation which was obviously from the outset going to be quite complicated. We decided what we would do was to take each patient in turn and investigate them as an individual case.

"The hospital had given us a number of names as a starting point and we had a number of meetings with the NHS team and asked them to go away and do some more research across a whole range of inexplicable respiratory arrest incidents within the hospital."

A team examined all the cases of patients being transferred from A&E to the critical care unit.

DCI Bierne, said: "We looked into cases where concerned relatives had called up as a result of press interest. Out of 27 cases which were the subject of a full police investigation, 18 victims were identified. Geen was the common denominator.

"The problem was that the hospital had had their suspicions, which had not been acted upon. In terms of evidence or any investigation, it was all quite superficial. We had to go away and look at each case to see what the evidence was and then go and gather that together."

Det Supt Taylor said: "We had a number of tracks to our investigation. One was, were these respiratory events inexplicable in terms of the underlying medical condition?

"If they weren't, we had something suspicious. It was for the experts to tell us in their opinion what caused the clinical events."

He added: "I would like to thank the staff of the NHS trust, particularly those working at the Horton.

"We have put them through a great deal of inconvenience. Part of our investigation has been to look at each patient in turn and some doctors and nurses have had repeated visits from our investigators.

"They have been incredibly supportive."