He walked off. Still, Hamish waited until at last the pathologist emerged and headed for his car. Hamish rushed over to him.

"What's the verdict?"

"Oh, it's yourself," said Sinclair, the pathologist, sourly. "It looks like an overdose. Anderson said he took heroin."

"What's a lethal dose?" asked Hamish.

"In a non-tolerant person the estimated lethal dose of heroin may range from two hundred to five hundred milligrams, but addicts have tolerated doses as high as eighteen hundred milligrams without even being sick. But there's an odd thing about heroin addicts." Dr. Sinclair leaned his cadaverous body against his car and settled down to give a lecture. "The reason for tolerance to heroin is partially conditioned by the environment where the drug was normally administered. If the drug is administered in a new setting, much of the conditioned tolerance will disappear and the addict will be more likely to overdose. Some pundits in the States believe that most of the OD cases are because of adulterated heroin. But oddly enough, British addicts who get clean heroin have about as high a mortality rate as Americans who shoot street crap. The health problems of addicts come from the use of needles, the presence of adulterants in the drug, the poor nutrition and health care associated with the hard-core addict-"

"Wait a bit," Hamish interrupted. "I saw Tommy today and he was healthy and happy."

The pathologist sighed. "Any addict is a tricky person. Very sneaky. He could have been talking to you and planning all the time in his brain when he was going to shoot up."

"Could the dose have been forcibly injected?"

"There are no signs of violence or of forced entry to the chalet."

"There wouldnae be any signs of forced entry. He probably kept his door unlocked day and night. I wonder about that book he was writing," murmured Hamish. "Oh, dear, I think that must be the boy's parents arriving."

A stolid, middle-aged couple were getting out of a police car. The woman, plump and matronly, was weeping, her husband with the blank look of shock on his face.