The police said that a case has been registered and an investigation is underway. (Representational)

A 22-year-old man was killed allegedly by his friends in Uttar Pradesh's Gorakhpur on Sunday, the police said.

After the incident, locals and the victim's family members staged a protest demanding arrest of all the accused.

"The police did not register our case. Four people were detained by police and they let one go," the man's sister-in-law said.

The police, however, said that a case has been registered and an investigation is underway.

"Abhishek Jaiswal went out with his four friends. His family alleged that they killed him. We have registered the case and action will be taken against the accused," senior police officer Arvind Pandey told reporters.