Can anyone identify this plant from Bangladesh?
The genus is Lantana, of Verbenaceae. That particular one could perhaps be L. camara. There's a number of papers that exist which study L. camara in Bangladesh, just some examples:

http://link.springer.com/article/10.1007%2Fs11676-007-0060-6

http://www.banglajol.info/index.php/BJB/article/view/1513