The murderer pleads guilty after being detected

At 00:05 on May 8, the operative managing center of Yerevan city department of the RA police received a report from an unknown citizen informing that a fire had broken in building 20/A on Arzumanyan street. 
After fire extinction the task force found Mariam Hunanyan’s, DOB 1991, body in the sitting room of the apartment number 8.
A criminal case was initiated under section 1 of article 104 of the Criminal Code of the Republic of Armenia.  
Forensic medical examination was assigned. 
At 19:00 on May 19 officers of Yerevan city department of the RA police along with officers of Mashtots police division on suspicion of having committed a murder detained David T., DOB 1987, in one of the apartments located in Quchak area, Avan.
The detainee confessed that about 23:20 on May 7 he paid a visit to Mariam Hunanyan and killed her, cutting her neck with the kitchen knife he was carrying.
The crime  instrument - knife - has been seized.
David T. is arrested.
The preliminary investigation is underway.