Mohan Kumar Vivekanand, born in 1963 in Karnataka, India, worked as a primary school teacher specializing in physical education from 1980 to 2003.

Between 2005 and 2009, Mohan Kumar targeted unmarried women aged between 22 and 35 who were seeking marriage but faced challenges due to dowry expectations. He lured these women by promising marriage without demanding dowry, exploiting their vulnerabilities. ​

After gaining their trust, Kumar would convince the women to elope with him. He took them to various locations across Karnataka, where they would spend the night together. The following day, he would suggest they take contraceptive pills to prevent pregnancy. Unbeknownst to the victims, these pills were laced with cyanide. He instructed them to consume the pill in public restrooms, warning that it might cause nausea. Once the victims ingested the poison and succumbed, Kumar would rob them of their jewelry and flee the scene. ​

Kumar's crimes went undetected for years due to the scattered locations and the assumption that the deaths were suicides. However, in 2009, the disappearance of a woman named Anitha led to a breakthrough. Investigations revealed that Anitha had been in contact with another missing woman. Tracing the phone records led authorities to Mohan Kumar. Upon his arrest on October 21, 2009, police found cyanide tablets, multiple mobile phones, and jewelry belonging to Anitha in his possession. ​

In 2013, after a trial lasting two years, Kumar was convicted for Anitha's murder and sentenced to death. However, in 2017, the Karnataka High Court commuted his death sentence to life imprisonment. By 2020, he was found guilty of murdering a total of 20 women, solidifying his status as one of India's most notorious serial killers. ​