Since the loop-road was somewhere ahead of Harper, and on his wrong side, it was very likely that Alderson and the chased car had come from the opposite direction, or towards him.
He glanced at his watch. It said six-twenty. He had found Alderson at four-ten, a little over two hours ago. That could put the murderers the best part of a hundred miles away, if they'd kept going non-stop. Probably the police had been alerted over a huge area by an eight-state alarm.
It wouldn't do much good. There was no adequate description of the fugitives and none at all of their car. "A tall, blond fellow" just wasn't enough to go upon.
He let a few miles go by until he saw a service-station on the opposite side — the side that, in Harper's theory, Alderson and the killers had used. He crossed and pulled up near the pumps; two attendants came over.
"Were you fellows on duty around four o'clock?"
Both nodded.
"See anything of a prowl car driven by a trooper named Alderson? Car Seventeen, it was."
"I know Bob Alderson," said one. "He was around a couple of times this morning."
"Not between three and four?"
"No." He thought a bit. "Or if he was, I didn't see him."
"Me neither," said the other.
Their minds told that they spoke truth; Harper knew it with absolute sureness. So far as he was concerned, they need not have opened their mouths.
"Anyone else here who might have noticed him around that time?"
"Only Satterthwaite. Want me to ask him?''
"I'd appreciate it."
The attendant went out of sight around the back of the building. It made no difference. Harper could hear them mentally, though their voices were out of reach.
"Hey, Satty, a fellow here wants to know if you saw anything of Bob Alderson two or three hours back."
"Nary a sign."
He came back. "No luck, Satty didn't see him."
"Anyone now off-duty who was here at that time?"
"No, mister." He showed curiosity. "Like me to tell Bob you're looking for him, if he happens along?"
"He won't be along — ever," said Harper.
"What d'you mean?"
"Some hoodlum shot him down around four. He's dead."
"Lord!" said the attendant, going pale.
"You'll have the police here asking similar questions, sooner or later." Harper gazed up the road. "Know of any place on his patrol where Alderson was in the habit of stopping?"
"He'd often grab a coffee at the Star Café."
"Where's that?"
"Four miles along, on the crossroads."
"Thanks."
He pulled out, drove fast. Two miles farther on, he came to another filling station, this time on his own side of the road. Turning in, he put the same questions.
"Sure I saw him," said a laconic, sandy-haired youth. "Didn't notice the time but it must have been about three hours back."
"Was he chasing somebody?"
The other considered this and said, "Yes, now that I come to think of it, maybe he was."
"What happened?"
"One of those low-slung green Thunderbugs went past in a hell of a hurry, and Bob came half a mile behind — like he'd no time to waste, either."
"But you aren't positive that he was pursuing the Thunder-bug?"
"I didn't think so at the time. Most of the stuff on this road moves good and fast — but now that you mention it, I guess he may have been after that car."
"Did you notice who was in it?"
"Can't say that I did."
"Did anyone else see this? Was anyone with you at the time?"
"No."
Harper thanked him and pushed on. So far, he'd gained one item: a green Thunderbug. He didn't congratulate himself on that; the police would find it themselves before the night was through. He was one jump ahead of them solely because he was concentrating on one specific line of search, while they were coping with a hundred. Harper had great respect for the police.
At the Star Café, a pert waitress reported that Alderson had eaten a meal there and left about one-thirty. Yes, he'd been by himself. No, he hadn't shown particular interest in any other customers or departed coincidentally with anyone else. No, she hadn't seen a tall, blond fellow with a green Thunderbug.
One of the other girls had seen Alderson go up the left-hand crossroad.
Harper took that road and kept the accelerator pedal well down. Fifteen minutes later he found a tavern keeper who had seen Car Seventeen. Yes, he had thought at the time that Alderson was after someone, probably a kid in a hot-rod.
Seven miles farther on, Harper struck another filling station. An elderly man came out and handed him news worth having.
"Shortly after three, a Thunderbug hauled up to the pumps for ten gallons of alk. There were three fellows and a girl in it. The girl was sitting in the back with one of the fellows. She kept giving me sort of appealing looks; I had an idea that she wanted to scream, but didn't dare."
"What did you do about it?"
"Nothing, at that moment. I was by myself and I'm not as young as I used to be. Those three could have bounced me on my head until my brains fell out."
"So what then?"
"They paid and pushed off; as soon as they'd got up a bit of speed, I skipped into the road for a look at their plates."
"Did you get the number?" asked Harper.
"No. I waited a mite too long. I hadn't my glasses on, and the figures were too fuzzy to read." The oldster frowned, regretting the lost opportunity. "Couple of minutes later a prowl car came along. I flagged it down and told the trooper about this girl. He said he'd look into the matter, and went after the Thunderbug at a good clip." His rheumy eyes quested hopefully. "Did he latch on to something?"
"Yes — a coffin."
"Good God!" The oldster was visibly shaken. "And I sent him after them."
"It isn't your fault, Pop, you did the best thing in the circumstances." Harper waited a minute for the other to recover, then asked, "Did those fellows say anything to indicate where they'd come from or where they were going?"
"They spoke exactly one word and no more. The big blond one dropped his window and said, 'Ten!' I asked about oil and water, but he shook his head. The girl looked as if she'd talk plenty once she got started, but was too scared to begin."
"What did this bunch look like? Give me as complete and detailed a description as you can manage."
The other licked his lips and said, "The blond one was doing the driving. He was a husky guy in his late twenties-yellow hair, blue eyes, strong chin, clean-shaven, good looking and intelligent. You'd have called him a nice kind of fellow, if his eyes hadn't been meaner than a snake's."
"No facial scars or other identifying marks?"
"Not that I noticed. Tell you what, though — he was pale. So were the other two guys. You know, whitish — the way they get when they've been bottled up quite a piece." He gave Harper a significant glance.
Harper nodded. "As if they've just come out of jail. They've escaped or been paroled — more likely the former, by the way they were acting."
"That's how it looks to me."
"Had they been hitting the bottle?" inquired Harper, sensing a possible lead at wherever the stuff had been bought.
"Far as I could tell they were cold sober."
"What else can you add?"
"The fellow sitting alongside the driver was another husky, about the same age: Black hair, gray eyes, clean-shaven. He was just as pale-faced, just as mean-looking. I never got a proper look at the third one in the back."
"How about the girl?"
"Around twenty or twenty-one — brown eyes, brown hair, a bit on the plump side. Attractive, without being a stunner. Wearing a mustard-colored coat, yellow blouse and a string of amber beads. Her hand was up by the window and she had a birthday ring with an opal in it."