A question that hopefully someone can answer. Why would someone...

A question that hopefully someone can answer.
Why would someone sell shares in ATU at the close of trade for 29c v the 31c it was trading for most of the day.
There was a turnover of 987k plus shares traded today.
Yet at the close of trade 3 seperate parcels of shares, 6, 6 and 62 for a total price of $21.46.
They were the last trades at 4.10pm.
Were they trying to influence perceptions for tomorrow’s trading?
Can someone shed some light please.