Prosecutors announced Friday they have opened a money laundering investigation against Peru's first lady Nadine Heredia.

Heredia, the wife of President Ollanta Humala, is accused of having received thousands of dollars in unexplained income in her bank account several years ago -- at around the same time her husband allegedly received illicit funds from various Venezuelan companies.

Prosecutors said the funds that were allegedly deposited into Heredia's bank account totaled some $215,000 and were used by her husband to finance his presidential campaign.

Prosecutors said they have asked handwriting experts to examine bank deposit slips allegedly signed by the first lady.

All the funds ended up in the account of Heredia, who is also chair of Peru's Nationalist Party and a potential candidate herself when the nation holds its next presidential election in April 2016.