Finally watched Gattaca. One question about the plot (SPOILERS)

Finally got around to watchingGattaca. Surprisingly good movie. I had have heard it mentioned over the years, but never with a big recommend. Wish I had watched it sooner.

One element of the plot I did not quite understand -

(SPOILER)

[SPOILER]Near the end the protaganist’s brother is revealed to be the chief police detective. But in doing the search on the “invalid” the detective never makes mention of this, nor does his second in command. Is there some part of the action I missed. The invalid’s picture is obviously young Vincent. Did the Chief know the suspect was his brother from the beginning?

Also, I did not realize the Chief Detective was his brother until the end. Maybe I wasn’t paying close enough attention to the looks of this brother when they were young men. Was this something obvious to everyone else?.[/SPOILER]