Boulder, Colo., police said the possibility of a feud between the Kappa Sigma fraternity and Sigma Alpha Epsilon that may have led to the bombing of the Sigma Alpha house last weekend.

The small fire caused minor damage to the Sigma Alpha Epsilon house but it was followed by a sizable brawl in an nearby alley that seriously injured one participant.

The Daily Camera newspaper in Boulder said Wednesday that detectives were also looking at residents of a neighboring apartment building.

The Daily Camera also said the Alumni Interfraternity Council at Colorado sent a letter to parents this week stating that Kappa Sigma members weren't involved in either incident.

"Neither the Kappa Sigma chapter nor its members were involved in either incident," the letter stated. "Reports of any Kappa Sigma involvement are categorically wrong."