She told a friend on WhatsApp that she loved Muslims after being questioned over her friendship with the man.

Police said screenshots of this exchange were shared on social media.

Five people from Hindu hardline groups also visited her house on Saturday to warn her parents, police say. The 20-year-old killed herself the same day.

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The police initially registered a case of suicide, but widened their investigation after reports about the role of social media in her death started to emerge on Monday.

K Annamalai, a senior police officer Chikkamagaluru district, told the BBC that the woman had left a suicide note.

"She has mentioned that there was a photo of her with a man from another religious community. People started commenting about it and cast aspersions on her character," he said.

He added that he killed herself after five persons went to her house and "complained to her mother that she was in love with a Muslim man."

He added that the police had arrested one person, and were searching for others.

'A young life lost'

BBC Hindi's Imran Qureshi, who has seen the screenshots, said her WhatsApp messages were quickly shared in the district.

In the messages, she is advised not to get "involved" with a man from another faith. She replies: "But I love Muslims."

She adds that she doesn't find anything wrong in being "associated" with members of any religious community.

Mr Annamalai said "whoever has criticised the woman, whether on Facebook or WhatsApp, would be arrested".

"We believe it amounts to harassment due to which a young life has been lost. We are taking this case seriously because it wasn't her fault," he added.

In recent years, India has witnessed Hindu-Muslim tensions over what has come to be known as "love jihad".

The term has been popularised by radical Hindu fringe groups, who accuse Muslim men of participating in a "conspiracy to turn Hindu women from their religion by seducing them".