European football's governing body UEFA will study the match reports on Monday before deciding whether to launch proceedings against the Bulgarian Football Federation over the racist abuse during Friday's Euro 2012 qualifier with England.
Bulgaria coach Lothar Matthaus apologised for the abuse after the game and now UEFA will assess the evidence before deciding what to do.
A UEFA spokesman said: "UEFA are aware of the situation. We will study the reports, including the delegate's report, on Monday."
Wayne Rooney and Theo Walcott said they could hear the abuse clearly, although some of his team-mates did not notice.
"As players we could hear it on the pitch," Rooney said. "It has been going on for years and it is not right. It needs to stop and hopefully something can be done about it."
"I was aware. It was very clear," said Walcott immediately after the 3-0 win. "I ignored it. But that is me. I think the FA will deal with that and I don't want to comment. The result was the important thing."
The Football Association have already made their feelings known to their Bulgarian counterparts, in addition to the UEFA match delegate.
"I can't say anything about this as I am not really aware of it," added Matthaus.
"In my capacity as the manager, I cannot comment on such things, but it's pitiful for things like that to happen.
"And, as a result of that, I'd like to apologise on behalf of the Bulgarian Football Federation."