A Presbyterian minister in the town, the Rev. Alan Johnston, said Rangers supporters were drinking heavily while watching Sunday's Rangers victory at pubs in central Coleraine and then drove across a bridge to the Catholic area, Somerset Drive.
A Catholic politician in the town, John Dallat, accused an outlawed Protestant paramilitary group, the Ulster Defence Association, of responsibility.
Rangers enjoys support exclusively from the British Protestant side of the community in Northern Ireland, while archrival Glasgow Celtic draws support only from the Irish Catholics.
Those sectarian allegiances fuel street fighting, and occasionally worse, in both Glasgow and across Northern Ireland, particularly when the two teams play each other or when the annual league championship — typically won by one of the two — is determined. Celtic, league champions the previous three years, finished second Sunday.
Police in forensic suits erected a tent Monday to preserve evidence at the spot where McDaid died. Nearby, someone had tied a green-and-white Celtic scarf to a pole, and teenagers wearing Celtic clothing huddled on street corners drinking from beer cans and shouting anti-Protestant slogans.
The officer leading the murder investigation, Detective Chief Inspector Frankie Taylor, appealed to the Catholic minority in the town not to retaliate.
Taylor said the dead man had four children, did volunteer youth work in the town, and had been encouraging local Catholics to cooperate with Northern Ireland's traditionally Protestant police. He described McDaid as "a man who would do anything for anybody."
In Northern Ireland, where Catholics and Protestants attend separate school systems, sports divide rather than unite the population. Protestants back rugby, Catholics their homegrown Gaelic football and hurling.
Both sides like soccer — but rarely root for the same teams. In international competitions, Catholics back the Republic of Ireland soccer team, Protestants the Northern Ireland squad. Many Belfast pubs refuse to admit customers if they are wearing soccer jerseys or scarves, particularly the rival Glasgow colors, because of the likelihood it will spark a fight.