5:00 PM -- Comcast Corp. (Nasdaq: CMCSA, CMCSK) has not fingered any individuals yet, but the MSO evidently has reason to believe that foul play may have contributed to an incident during Sunday's airing of the Super Bowl that caused some viewers in Tucson, Ariz., to see more than they bargained for: a 10-second video clip of pornography.

According to multiple reports, the short clip popped up late in the fourth quarter soon after Arizona Cardinals wide receiver Larry Fitzgerald scored a go-ahead touchdown. The offending material, reportedly an excerpt from an adult channel called Club Jenna, was isolated to Comcast's system in suburban Tucson, where the MSO serves about 80,000 customers.

The incident also was isolated to the standard-definition broadcast. The hi-def feed was delivered uninterrupted. Customers for Cox Communications Inc. , the region's dominant cable provider, did not report seeing the offending clip or otherwise report an interruption during the Super Bowl broadcast.

Comcast is investigating the situation and pursuing all possible scenarios, but has yet to reach any conclusions about the source of the interruption or who might have been involved.

"We are mortified by last evening's Super Bowl interruption and we apologize to our customers," Comcast spokeswoman Jenni Moyer said in a written statement. "Our initial investigation suggests this was an isolated malicious act. We are conducting a thorough investigation to determine how this happened.”

In the meantime, Comcast is considering giving credits to affected customers in Tucson.

KVOA-TV, the Tucson-based affiliate, is also investigating. "When the NBC feed of the Super Bowl was transmitted from KVOA to local cable providers and through over-the-air antennas, there was no pornographic material," KVOA president and general manager Gary Nielsen said in a statement.

— Jeff Baumgartner, Site Editor, Cable Digital News