Additional Conservator of Forests Tabibur Mia said it all happened at Choutali Beat of sector 2 in the forest on Thursday.
"An 18-20 feet python has devoured an 18 kg deer...I rushed there on receiving news and watched the whole thing to the end," he told bdnews24.com.
He said the Forest Department hailed it as a positive sign as it indicated a return of balance in the ecosystem.
In the absence of food, such animals stray into human habitation. But this time this did not happen and this indicated a revival of the food chain balance, he said.
Many onlookers thronged the spot to catch a glimpse of the sight.