The boy hit the girl on the head with an axe after learning that she was to be married to someone else.
Two days after an 18-year-old girl was found murdered in the district, it has turned out to be a case of attack by an alleged jilted lover, with police arresting him and his friend.
Chidambaram's Annamalai University MA first year student Arasan, 21, surrendered before police in nearby Porayar last night while his college mate Rajmohan was arrested today, police said.
Deepika, a second year BA student of a nearby college, was found murdered on September 20 with severe head injuries in a dry canal in her village Appurasaputhur in the district after she went missing the previous night.
The murder is the latest in a series of such fatal attacks on young women in the state by jilted lovers in recent months.
Arasan allegedly confessed to hitting Deepika with an axe following a quarrel between them over arrangements being made for her marriage with another person, they said.
Arasan claimed that he and Deepkia were in love and he had met her on Monday night after coming to know about her marriage. He allegedly hit Deepika with the handle of the axe during a heated argument.
His friend Rajmohan was standing nearby and both fled the scene in a two-wheeler.
Based on Arasan's statement, police arrested Rajmohan this morning. Both were produced before a court which remanded them to judicial custody.
This is the fifth such fatal attack on young women in the state by jilted lovers since the brutal killing of software professional Swathi at a railway station in Chennai in July.
A 23-year old woman was allegedly stabbed to death by a man on September 14 in Coimbatore for rejecting his proposal.
The man later attempted suicide.
Last month, an engineering student was clubbed to death in her classroom in a private college by her senior in Karur while a 25-year old teacher was killed in a church by a man, who later ended his own life.