The accused were arrested within 12 hours of the incident being reported, they added.
On July 27, the police were informed about an injured man lying in Sector 19, Dwarka. He was taken to a hospital where he was unable to speak but he wrote his name as Kamal Singh Yadav, a native of Banda in Uttar Pradesh, the police said.
Police analysed the call detail records of the victim's phone and it was found that he had come to Delhi on July 25 from Gujarat.
It was found that the victim was in touch with a woman, who works as a maid in Dwarka Sector 10, they added.
She told the police that Yadav was her phone friend and had come to meet her from Gujarat.
She said one Rakesh, who is her sister-in-law's husband, was jealous about her closeness to Yadav. The woman was in a relationship with Rakesh, they added.
She revealed that Rakesh had informed her about the stabbing incident and he was going to leave Delhi from Nizammuddin Railway Station for his native place in Banda, UP.
Subsequently, Rakesh was nabbed from at the station and he led the police to his co-accused.
On the night of incident, Rakesh and his accomplice invited Kamal and gave him heavy drinks and cut his throat with paper cutter blade and took away his mobile and wallet so that the victim could not be identified, they added.