The police found that the man and his girlfriend had come to the hotel on Friday.
A 28-year-old man has been arrested from Uttar Pradesh for allegedly killing his girlfriend inside a hotel room here following an argument, police said on Tuesday.
The accused has been identified as Shivam Chauhan, a resident of UP's Ghaziabad, they said, adding that the man was in a relationship with the woman for the past four years.
On Sunday, the police received information that the body of a woman had been found in one of the rooms of Hotel Lak Residency in southwest Delhi's Vasant Kunj area.
The deceased was identified as a resident of Kishangarh in Vasant Kunj, a senior police officer said.
The police found that Chauhan and the deceased had come to the hotel on Friday, but the accused had left the day after, the officer said.
The police conducted raids and apprehended Chauhan from Mitrauli in Uttar Pradesh, Deputy Commissioner of Police (southwest) Gaurav Sharma said.
During interrogation, Chauhan told the police that the women had been deceiving him and was in a relationship with another man named Utkarsh for the past few days, the DCP said.
Utkarsh had been calling the woman constantly on Saturday when they both were in the hotel room, the accused told the police.
Chauhan said when he asked the woman about the calls, she made an excuse, saying Utkarsh was her sister's boyfriend, police said.
The accused told the police that after listening to the woman's lies, he had a heated argument with the her and banged her head on the floor which led to her death, officials added.