Alfred claimed that he was nowhere near the house when the butler was murdered. His was that he was across town at the grocery store when it happened.

he is lying

Explanation:

look for evidence like time dates witnesses and other evidence like hair blood or others also check the stores cameras and make sure he did not hire anyone.

pitch- the definition of pitch is as follows:

"the quality of a sound governed by the rate of vibrations producing it; the degree of highness or lowness of a tone."