My opinions only, no facts here:
Quoting from an interview with Holly's brother at
http://edition.cnn.com/TRANSCRIPTS/1108/04/ijvm.01.html
"Well, I stated originally and never wavered from the description of the man being approximately 5`10 and 200 pounds."
Let us pretend that this interview happened and that this statement was made. This is much more specific than the watered-down FBI description of the kidnapper, and could (and should) be emphasized by the defense attorneys.
In spite of considerable research, I am unable to find an official description of the size and weight of the recently-arrested younger brother of the main suspect. Keep looking out for this info and notify me if you see it. I evaluated file photos of the younger brother in two ways. First, I assumed that his head is about as long as his older brother's head (his older brother's height is known). In the second test, I assumed that the buttons on his jail uniform are 9/16 of an inch in diameter. Either way, he comes out shorter and certainly thinner in stature than the implied stocky 5' 10" 200 pound kidnapping suspect, as supposedly preferred by Holly's brother. Although both of the tests I applied are qualitative and subject to perspective errors, I doubt that the younger brother of the main suspect is the kidnapper because of how thin and sleight he appears.
But, I do not disagree when the DA implies that someone else may be arrested. They can start this process by arresting and properly charging a male who fits the witness description of the actual kidnapper. This is the only man I am interested in at the present time.
Sleuth On!