Reply #6: A lunch riddle

[Merrick]

Detective Sam Shade paid a visit to the home of the prime suspect in a daring mid-day fish market robbery. Upon knocking on the door, Sam noted that it took an exorbitant amount of time for the suspect to answer. Sam eventually attributed this to the suspect’s waddling gait which he suspected was being exaggerated. Acting as if he had nothing to hide, the suspect invited Detective Shade to come in out of the heat of the afternoon and offered him some iced-tea, which Sam accepted before getting down to business.

“Where were you at 1pm this afternoon?” Sam asked.

Looking as innocent and baffled as possible, the suspect replied, “Why, I was out being fitted for a new tuxedo for my friend’s wedding.”

“AHA! I’ve caught you now!” Sam exclaimed triumphantly.

How did Detective Shade know the suspect was lying?