Bijendra Kumar, 23, was held after the killing Wednesday by other students and security guards at St. Xavier's College in Ranchi in northeastern India, the Hindustan Times reported. He was allegedly beaten before police arrived.
The victim, 18, was identified only by the name Khusbu. Kumar's mother said the young woman's family had objected to her marrying Kumar and her uncle had beaten him.
Kumar told police he had planned to take his own life.
"We were in love for the last five years, but our parents did not allow us to unite, so we decided to die together. After killing her, I was about to kill myself when they caught me," he said.