Dr Landau came out into the corridor where Doyle was pacing impatiently. "Do you want to see the body?"

"No, thanks. Just tell me if it was a natural death."

"It most certainly was not a natural death." The doctor had a photograph in his hand. "See this? It's an injection mark. And it's not an ordinary needle that would be used to give medicine, or even draw blood. This is from a big syringe, big enough to inject a sizable air bubble into the vein."

"An air bubble!" Doyle peered at the picture.

"To be more precise, an air embolism. Air gets into the circulatory system and can block a blood vessel. It can happen with lung injuries, or from explosions, and we sometimes see it in scuba divers." Landau said pointedly, "If you don't know what to look for, it might seem that the patient died from natural causes, such as a heart attack or a stroke. Since the victim had been receiving injections at the care home, this particular mark would probably have been overlooked in a normal autopsy."

"So it's murder."

"Quite."

Doyle thought for a moment. "Just how difficult would it be to do this injection?"

"Not difficult at all. Anyone with the training to perform intravenous injections or draw blood could do it."

"That's just great," said Doyle heavily. "Most of the staff at New Horizons must have that knowledge."

"New Horizons?" Landau looked interested. "I didn't know that was your assignment. How is Rob Pearson?"

"You know Dr Pearson?"

"We interned together. Rob was always more interested in the administrative side of medicine, so I wasn't surprised when he took over New Horizons. From what I hear it's a first class establishment."

"It's all that," said Doyle. "They've had a few dodgy deaths but I think it's only to be expected. They do get some pretty sick people."

"Yes." Landau reflected for a minute, then said, "I haven't thought of Rob in years. Wonderful chap. Such a shame it didn't work out with him and Connie." At Doyle's questioning look, he went on. "Connie Towers. They were actually engaged but somehow it didn't come off. Ah, well."

"There's a Connie Towers working at New Horizons at the front desk."

Landau was surprised. "The name must be a coincidence. It can't be the same person. Connie was a nurse. One of the best I ever worked with."