"South Lake isn't such a good location," Penny said thoughtfully, "I've heard Father say that a great many disreputable firms operate there. I know once he traced stolen furniture to a dealer on that street."
"I hope I didn't buy a stolen wheel," Susan declared. "Was that what you had in mind, Penny?"
"I thought of it right off. But I haven't any reason for saying it. For all I know, your tire may be a legitimate bargain."
"I wish there was some way of finding out for certain," Susan said anxiously.
"Let's look for the serial number. The wheel should have one."
Penny moved closer to inspect the new purchase.
"The number is here all right," she acknowledged.
"Then the tire wasn't stolen," Susan said in relief.
Penny shook her head. "I'm not so sure of that, Sue. It looks to me as if these numbers have been changed. Wait a minute!"
She darted into the house, returning with her father's magnifying glass. Using it to study the figures upon the wheel, the girls could plainly see that the numbers had been altered.