MANILA, Philippines - Bureau of Internal Revenue (BIR) Commissioner Kim Henares hinted on Wednesday that Chief Justice Renato Corona's wife, Cristina, may face an investigation by the tax bureau over the P11-million La Vista property that the couple bought in 2003.

During the Corona's impeachment trial hearing, Henares said the BIR found out only recently that Mrs. Corona bought the property without any clear source of income.

In an interview with ANC after the hearing, the BIR chief said the case "is a wake-up call for us that maybe we should look into the records."

However, she declined to say directly if Mrs. Corona will be investigated.

"I am caught in a very difficult situation because it is a very confidential matter whether we would investigate or not," Henares explained.

"Siguro, it's enough to say na kung mayroon dapat mangyaring imbestigasyon, the public should be assured that the BIR will conduct whatever is needed or required, without saying anything other than that," she added.

"It's a confidential matter. You will know about it if it warrants a filing of a criminal case. If it's a civil case, you will not know about it unless she sues us," Henares said.

She said a tax investigation can either lead straight to filing a criminal case against a person or the BIR asking the person to produce documents to prove his or her innocence.

"If we don't have that strong an evidence, we go and summon the person, ask them to provide us with their income documents, explain where all these things come from," the BIR chief said.

"It can take either way. I'm not talking about Mrs. Corona's case. I'm talking about the general sense," she added.