Sometimes Ethernet captures include an FCS at the end of the packet.

Sometimes Ethernet captures include an FCS at the end of the packet.

An Ethernet trailer is only needed to pad the packet to 60 bytes of
Ethernet header plus payload; if the packet has what appears to be a
trailer, and it's 4 or more bytes (i.e., long enough to include an FCS),
and the Ethernet frame was claimed to have 64 or more bytes (i.e., it
has at least an FCS worth of data more than the minimum 60 bytes),
assume that the last 4 bytes of the frame were an FCS.

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