24 Muslims from Bangladesh illegally entered the US from the Mexican border in March, 2018

Not only is Bangladesh a Muslim majority country (at 146.6 million Muslims in the 2011 census, the 4th largest Muslim country in the world), but Islamic extremism has been extremely high in Bangladesh since 2013.

Since 2015, many Bangladeshis have joined ISIS and al-Qaeda and commit frequent attacks on Christians, Hindus and Shi'a.
 
Regarding the Bangladeshis who entered in March, Border Patrol Agent Hector Garza said:
 
“The arrest of these people from Bangladesh shows there is a clear pipeline from the Middle East through Mexico to the southern border of Texas … We have been lucky to catch these groups but there is no telling how many other people from countries that sponsor terrorism could be utilizing that same pipeline.”
 
Seven Bangladeshi crossed into the U.S. on March 13th.
Nine Bangladeshi crossed the border between March 20 and 22.
Eight Bangladeshi on March 28 and 29th.

Bangladesh has a rapidly growing number of ISIS and al-Qaeda cells. Photo right is of eight Bangladeshi members of Islamic State.

Since 2015 members of ISIS and al-Qaeda in Bangladesh have been targeting and killing Shi'a and Ahmadi Muslims, Christians and Hindus. Many of their targets are hacked to death.

The BBC reports in various articles that Islamist extremism has been on the rise in Bangladesh.
https://www.bbc.co.uk/programmes/p040s3gs;
http://www.bbc.com/news/world-asia-36203768;
https://www.youtube.com/watch?v=ka7grHHKTe8
 
Reports on Border Patrol arrests.
http://www.breitbart.com/texas/2018/03/24/9-bangladesh-nationals-arrested-illegal-border-crossings/
http://www.breitbart.com/texas/2018/03/18/border-patrol-agents-arrest-7-bangladesh-nationals-2-days-near-texas-border/
 
Bangladesh has 146.6 million Muslims, which is the fourth largest in the world, constituting 90.4% of the total population as of 2011.
https://en.wikipedia.org/wiki/Islam_in_Bangladesh