One of the key figures in a scandal that led a Liberal MNA to resign has been arrested for talking to a witness.

Luigi Coretti, who was charged with fraud last year, was arrested by the Surete du Quebec on Thursday.

Representatives of UPAC, the permanent anti-corruption squad, said Coretti had spoken to a witness in the case which is strictly forbidden according to his bail conditions.

He is expected in court Thursday.

The whole scandal dates back several years and involves a former family minister and a security contract for Montreal police headquarters.

Coretti was the head of the BCIA security firm, which declared bankruptcy in 2010. He is accused of giving a credit card to then-Liberal family minister Tony Tomassi, and Tomassi is accused of using that card to pay for gasoline over an extended period of time.

When those allegations became public in 2010, Tomassi was ejected from the Liberal party, and was charged himself in 2011.

Coretti is formally charged with falsifying documents to obtain loans under false pretenses.