Whether it's impressionist paintings by Monet, athletic headgear or medical tubing, federal investigators claim Rocco DeSimone can turn it into a scam worth millions of dollars.

On the eve of his release from prison — a stay interrupted by a brief escape and manhunt — the 55-year-old art dealer faces a new indictment, this time accusing him of duping an inventor and others by claiming he had access to deep-pocketed business connections.

He pleaded not guilty Friday to mail fraud and money laundering charges during a hearing in U.S. District Court.

The U.S. Attorney's office wants DeSimone held in prison until trial even though his sentence on tax evasion charges expires Saturday. A judged ordered DeSimone jailed until a hearing on the issue next week.

Prosecutors argue the latest indictment is another progression in a criminal career that already includes impersonating a federal agent, an insurance fraud case and allegations DeSimone peddled a machine he claimed could turn rocks into rubies.

"He is an unrepentant, habitual con-man who moves from one fraudulent scheme to the next," Assistant U.S. Attorney Lee Vilker said recently in court documents.

DeSimone intends to fight the charges, said his attorney, Richard Corley.

"He is proclaiming that he is absolutely innocent of any wrongdoing, and he's presumed innocent by the court," Corley said. "No one should rush to judgment."

In 2005, DeSimone was convicted of tax evasion for claiming he owned the painting "Canal at Zandaam" by Monet for more than a year before selling it, a lie that saved him roughly $420,000 in taxes. But a jury acquitted DeSimone of charges that he cheated an elderly New York City art dealer of almost $2 million in the sale.

He was sentenced to more than two years in prison.

Even while free on bail to appeal his conviction, the art dealer continued running scams, according to prosecutors.

The indictment returned earlier this month suggests DeSimone fooled a doctor with relative ease. Prosecutors said DeSimone conned an inventor, Dr. Robert McKittrick, into giving him a one-third ownership stake in a device called the Drink Stik, which allows athletes to drink without removing their protective headgear.

DeSimone allegedly gained McKittrick's trust by claiming to have sold a painting on behalf of one of the doctor's friends. DeSimone promised he could market the Drink Stik and that Fidelity Investments CEO Edward Johnson III had offered to pay millions of dollars for it.

In fact, DeSimone did not know Johnson, prosecutors said.

When Raytheon Co. turned down the invention, DeSimone continued telling investors it was a "done deal," according to the indictment.

DeSimone convinced investors to give him $1.2 million in cash and $4.9 million in forgiven debts and property, including artwork and Japanese artifacts.

The FBI probe apparently prompted DeSimone's escape from prison, prosecutors said.

Alerted when federal agents searched his home on March 13, DeSimone fled three days later from a minimum security prison in Fairton, N.J., with the help of his wife and a family friend. He surrendered to authorities in Providence after four days on the loose.