Srimad Bhagavatam Canto 10, Chapter 44, Text 38

SB 10.44.38

tam samparetam vicakarsa bhumau
 harir yathebham jagato vipasyatah
ha heti sabdah su-mahams tadabhud
 udiritah sarva-janair narendra
As a lion drags a dead elephant, the Lord then dragged Kamsa’s dead body along the ground in full view of everyone present. O King, all the people in the arena tumultuously cried out, “Oh! Oh!”
Srila Visvanatha Cakravarti explains that many people in the audience thought Kamsa had simply been knocked unconscious when thrown from the lofty dais. Therefore Lord Krsna dragged his corpse so everyone would realize that the evil King was indeed dead. Thus the exclamation ha ha indicates how surprised the people were that the King was suddenly dead and gone.
The audience’s astonishment is also mentioned in the Visnu Purana:
tato haha-krtam sarvam
 asit tad-ranga-mandalam
avajñaya hatam drstva
 krsnena mathuresvaram
“Then the entire arena became filled with cries of astonishment as the people saw that the master of Mathura had been contemptuously killed by Krsna.”
Srimad Bhagavatam Canto 10, Chapter 44, Text 37
Srimad Bhagavatam Canto 10, Chapter 44, Text 39