Doesn’t Pharaoh remember Moses? His grandson, the guy he sent men to kill?

Exodus 5:1 says, “And afterward Moses and Aaron went in, and told Pharaoh, Thus saith the LORD God of Israel, Let my people go, that they may hold a feast unto me in the wilderness.

5:2 And Pharaoh said, Who is the LORD, that I should obey his voice to let Israel go? I know not the LORD, neither will I let Israel go.

5:3 And they said, The God of the Hebrews hath met with us: let us go, we pray thee, three days' journey into the desert, and sacrifice unto the LORD our God; lest he fall upon us with pestilence, or with the sword.

5:4 And the king of Egypt said unto them, Wherefore do ye, Moses and Aaron, let the people from their works? get you unto your burdens.”  OK, this is strange to me.  Pharaoh doesn’t remember Moses?  His grandson, the guy he sent men to kill because he killed an Egyptian?  Pharaoh must be dumb. Exodus 2:15 says, “Now when Pharaoh heard this thing, he sought to slay Moses. But Moses fled from the face of Pharaoh, and dwelt in the land of Midian: and he sat down by a well.”  God said he would harden Pharaoh’s heart not his head.  You would think he would call in guards to capture and kill Moses.  It isn’t like he didn’t know who Moses was?