Free The Madman Theory by Ellery Queen

And some bitterness.
    Earl Genneman, Junior, was a youth of seventeen or so, thin to the point of gauntness, wearing tight blue levis and a plaid shirt. He had a sharp chin, a big nose, and small red eyes. He was in the process of growing a beard. He strolled in with a truculent air.
    â€œTake a seat. I’m Inspector Collins, investigating your father’s death.”
    Earl Junior slumped on the sofa, fished in his pocket, brought forth a cigarette, and insolently tapped it on his knuckles.
    â€œNow tell me,” he said, “how I’m driving another nail into my coffin. All you squares do.”
    â€œIncluding your father?” asked Collins.
    â€œAll right, including my father!” The red eyes stared in a suffering sort of way. “Who cares about lung cancer? Hell, if I’m alive when I’m thirty, I’ll kill myself.”
    â€œThe man who killed your father was really doing him a favor?”
    Earl Junior gave a contemptuous grunt.
    Collins asked curtly, “Do you have any idea who did it?”
    The boy considered this. Collins watched him dispassionately. Small chance for comradeship between son and father. Earl Junior finally gave his reply. “Nope.” His tone mockingly said that he knew a great deal more than he was admitting. Bravado, Collins decided—sheer orneriness—and he rose.
    â€œSo long, sonny.”
    In the foyer he waited for Mrs. Genneman to come out of the library. She seemed distant, even cool. He pretended not to notice, promised to keep her abreast of developments, and left.
    He drove to the San Jose Police Department, where a clerk took him to the files. He found no significant reference to the Gennemans, to Buck James, Bob Vega or Myron Retwig. Redwall Kershaw was well-known, with arrests for drunken driving, disturbing the peace, malicious mischief, and illegal possession of drugs.
    Collins read the particulars of the drug charge with attention. Kershaw had been halted on a minor traffic violation near the racetrack. The arresting officer noticed Kershaw kicking parcels under the seat; he investigated and found them to contain unlabeled drugs which turned out to be various illegal stimulants. Kershaw pleaded that he was taking the parcels to a friend and had no notion what was in them but he refused to identify the “friend.” He had escaped lightly for his various derelictions, serving thirty days twice, with a year’s probation on the drug indictment.
    Collins returned to Fresno, arriving late in the evening. He drove directly home—it was a new three-bedroom split-level in Morningside Park, which Collins had bought because he disliked apartments.
    Lorna, his wife of two months, mixed highballs while Collins called headquarters. Rod Easley had gone home; the officer on duty knew of no important developments. Collins hung up and gave his attention to the fried chicken and country gravy on his bride’s menu. He praised them lavishly, having learned his lesson early. The chicken tasted like fried mortarboard, the gravy like unhardened plaster of Paris. It was the appropriate ending to a bad day.

5
    On Thursday, June 18, Inspector Collins arrived at headquarters to find Sergeant Easley already at work with license registrations. Collins sat down to help and by noon the job was almost complete. Of the cars which had entered the park during the period under scrutiny, four appeared suspicious.
    First was the ’62 Dodge registered to Nathan Wingate of Redondo Beach, with license registration LKK—3220. Nathan Wingate claimed that neither he nor his car had ever entered the General Grant National Park. Either Wingate lied, or the ranger had made a mistake noting down the license number, or the license had been faked. The car had entered the park early Wednesday morning—at the extreme edge of the critical period. Collins was not inclined to attach too much significance to this one.
    Next came a ’63 Oldsmobile