The body of 16-year-old Mahmoud Hrouk was located inside a home at Belmore Street, Fairfield East, on the morning of Sunday 17 May 2015.
He had suffered extensive injuries and been sexually assaulted.
Homicide Squad detectives have been investigating the incident under Strike Force McCahon.
Around 3pm today (Thursday 16 July 2015), Homicide Squad detectives arrested a 22-year-old Fairfield East man at Fairfield Police Station.
He is expected to be charged with murder and aggravated sexual assault.
Investigations are continuing.
Police are urging anyone with information in relation to these incidents to call Crime Stoppers on 1800 333 000 or use the Crime Stoppers online reporting page: https://nsw.crimestoppers.com.au/ Information you provide will be treated in the strictest of confidence. We remind people they should not report crime information via our Facebook and Twitter pages.