The body of Mr McErlain was discovered after police were called to a house in the Broombeg View area of Ballycastle at around 8.30 pm last Thursday.
Police said the 48-year-old suffered a “traumatic and frightening death” and described the killing as “a heinous crime”.
MIT detectives had been granted more time to continue quizzing the man over the weekend.
They were also given further time to question a 50-year-old man who was arrested on Friday.
He remains in custody at Coleraine PSNI station.
The 33-year-old will appear at Coleraine Magistrates’ Court on Monday.