An interception by Indianapolis Colts linebacker D'Qwell Jackson during Sunday's AFC Championship Game is what initially led to an NFL investigation into whether the New England Patriots intentionally deflated footballs during their rain-soaked victory, Newsday is reporting.
The newspaper, citing a person familiar with background of the matter, reported that Jackson, following his second-quarter interception, gave the ball to a member of the Colts' equipment staff, who noticed it was not fully inflated and informed Indianapolis coach Chuck Pagano.
According to the Newsday report, as well as WCVB-TV in Boston, Colts general manager Ryan Grigson was alerted about the ball in the Gillette Stadium press box. Grigson contacted NFL director of football operations Mike Kensil, who then told game officials during halftime.
New England, up 17-7 at that point, went on to win 45-7. The Pats scored three third-quarter touchdowns as heavy rain soaked Gillette.
On Monday, a league spokesman confirmed to ESPN that the NFL is investigating the matter. Vice president of football operations Troy Vincent told Pro Football Talk on Tuesday that the investigation will be completed within the next two to three days, but did not specify when the findings of the investigation would be announced.
"The team is in place in New England now interviewing staff members," Vincent said on PFT Live. "For a fan, you want to know that everything's equal. The integrity of the game is so important."
Asked by ESPN.com on Tuesday morning if he has heard from the NFL, Patriots coach Bill Belichick said, "Any questions on that, you should talk to them about."
On Monday, Pagano said he did not notice issues with the football, and he didn't specify when asked whether the Colts had reported the issue to officials.
"We talk just like they talk to officials [before the game], we have an opportunity to talk to the officials about a lot of things, things that you've seen on tape like the formations we talked about last week," Pagano said. "Every coach in the league gets an opportunity to visit with the officials about that kind of stuff before the game."
An underinflated football could be easier to grip and catch. NFL rules stipulate that footballs must be inflated between 12.5 and 13.5 pounds per square inch and weigh between 14 and 15 ounces.
Former NFL official Jim Daopoulos, in an interview with ESPN on Monday morning, explained the process in which footballs are managed. Two hours and 15 minutes before each game, officials inspect 12 footballs from each team and put a mark on them to indicate they meet the proper requirements and are good for usage. Then those footballs are given to the ball attendant.
There also is a second set of six footballs, used specifically for the kicking game, that are marked appropriately and remain in the possession of officials at all times.
"Officials check balls as they go into the game, and if the ball doesn't feel perfect, they can throw it out," Daopoulos said. "There is always the possibility that balls can lose air due to the conditions."
A team can be fined if it is found to be knowingly altering the weight of the football.
Patriots quarterback Tom Brady laughed when asked of the report Monday.
Tight end Rob Gronkowski took a similar approach via Twitter.
ESPN.com's Mike Reiss and ESPNBoston.com's Lee Schechter contributed to this report.