The body of Robert Flowerday, 64, was discovered at his home in Mill Road, Crumlin, on Sunday night.
He was last seen alive when he left Dundrod Presbyterian Church just before 1pm on Sunday.
The 33-year-old suspect has been taken to Musgrave Street police station in Belfast for questioning.
Mr Flowerday was last seen as he left church to cycle home to Crumlin, and was wearing a high-viz jacket.
Announcing the murder probe on Monday evening, Detective Chief Inspector Alan Dickson, from the Police Service of Northern Ireland's Serious Crime Branch, said: "Police were called to the scene after concerns were raised by a member of the public in relation to Mr Flowerday.
"When police arrived at his Mill Road home, they discovered his body inside."
He added: "I am appealing to anyone who may have seen Mr Flowerday between 12.45pm and 9.50pm on Sunday January 28 to come forward and speak to police.
"I am particularly keen to speak with anyone who saw or spoke with him at any time over the weekend, or anyone who was in his company."
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