Why does George think that he (Lennie) needs an alibi?Of Mice and Men, Chapter 5

George certainly feels the need to create an alibi because
he lets Candy make the announcement of Curley's wife's death and pretends to come in
like he didn't know what had already happened in the first place even though George does
know. George needed this time to get to the bunkhouse and grab Carlson's gun, although
the reading audience doesn't figure all of this out until at the end of chapter 6. So,
if the he you may be referring to is George, this is his
purpose.

Lennie, has no alibi and at this point in
the novel, it is difficult to create one. However, Lennie may need the protection of
George in order to escape this world with happiness and free from pain. Neither of these
needs fulfill the definition of an alibi, but they are closely related in that they
required a defense. They required a friend who would step in and interfere with the type
of justice that would have ensued otherwise. George well fulfills this role of
defense.