The accused was angry as the lecturer had rebuked him following a female student's complaint, they added.
The deceased, Rajesh Malik, was aged between 35 to 40 years, they said.
The accused was identified as Jagmal, a BA second year student, police said.
Jagmal, a resident of a village near Kharkhoda, today walked into the college in the morning and fired four shots at Rajesh, police said adding that the bullets hit Rajesh in the chest and arms. He was declared brought dead when taken to a hospital, they said.
The accused fled from the spot, police said.
"That is why he developed personal animosity against the lecturer," police said.
Police said Jagmal, who belongs to a farming family, was absconding and teams had been formed to nab him.
Rajesh is survived by his wife and two children.
Notably, a class 12 student had allegedly shot dead his school principal with his father's licensed revolver in Yamunanagar district in January this year.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)