If I understand correctly (please correct me if I am wrong) the Chicapu Indians you mention are known in US as Kickapoo (means 'he moves about, standing now here, now there'). The reason I believe this may be so is because of the info from the net below:
My uncle called them Chicapoo.He said they ended up near Muzquiz in a place called Nacimientos de los Indios, and that my ancestor somehow helped them set up there.
I have an article I got off the net from http://www.irc-online.org/bordline/1996/b120/b120indi.html
but I can't seem to get it now. Perhaps if you search with a search engine and type in Kickapoo Indians it may give you the site.
The article states the Kickapoo Indians were
"from the Great Lakes region, and that some settled in Coahuila. In 1832, US Army officials granted tribal members the right of 'safe conduct', allowing them to pass freely across the border. This right has been guarded jealously by the Mexican Kickapoo. An 1850 land agreement with Mexico granted members of the tribe the same rights as Mexican citizens and reserved for them a one-square-mile reservation called 'Hacienda El Nacimiento', near Muzquiz, Coahuila, where may still live."
"In the 1940s, after a brief period of instability, a number of factors forced the Mexican Kickapoo to move once again."
"The Mexican Kickapoo were particularly sought out as farmworkers, especially as the Bracero program wound down, because of their border-crossing abilities."
"In the 1980s the US Immigration and Nuturalization Service invited all Kickapoo living in Mexico to become US citizens even while continuing to reside in Mexico."
Like I said, I believe these are the same people as the Chicapu you mention. If so, the above is a brief history of them.