Strike or hit by pitch?

[msrock1954]

Was watching WCWS last night, Michigan -vs- UCLA and almost this exact situation occurred. High inside pitch that grazed the bat and hitter immediately looks at the ump and says it grazed her forearm. Ump initially called it a strike as he apparently did not see it hit her and only heard the ball hit the bat. He went to his partner at 1rst base and he apparently saw enough to say it did hit her so she was awarded 1rst base. From what I saw on the replay it did NOT hit her, but with the ball moving that fast it's hard to tell so I can't figure out how the 1rst base ump could tell??