A multimillion-dollar Roy Lichtenstein painting of an electrical cord that was sent out for a cleaning 42 years ago and disappeared was returned to its owner on Tuesday.

U.S. Attorney Preet Bharara, calling the recovery of missing or stolen art an "important mission" for the federal government, stood near the 1961 black-and-white painting, Electric Cord, as he described how American art dealer Leo Castelli bought it in the 1960s for $750.

"It is now worth about $4 million US," Bharara said. "Returning stolen art and artifacts is an important mission of this office, and it is always gratifying when we are successful."

Castelli sent the painting to an art restorer for cleaning in January 1970 and never got it back. He died in 1999. The painting resurfaced six years after the Roy Lichtenstein Foundation published an image of it on its holiday greeting card in 2006 and asked the art community to help find it.

Castelli's widow, Barbara Bertozzi Castelli, said she plans to display it in her Manhattan home "if I find a place to hang it." She said she had never seen it before Tuesday.

Bharara declined to say whether criminal charges will be filed against anyone in connection with the painting's disappearance.

Turned up in warehouse

The government said the painting turned up at a New York warehouse, the Hayes Storage Facility, which received it from the Quinta Galeria art gallery in Bogota, Colombia. The gallery had received it on consignment from Sally Goldreyer, the widow of the art restorer, Daniel Goldreyer, court documents show.

Sally Goldreyer said in court documents that the painting was discovered in the locker of one of her husband's employees after her husband died in 2009. She said the contents of the employee's locker were given to a friend who asked her to sell the painting for him, according to the court documents.

The government said the painting was going to be bought by the Quinta Galeria but Sally Goldreyer refunded the gallery's deposit when she saw an Internet posting saying the painting was missing.

Goldreyer signed an agreement with the government to return the painting to Castelli, though it said the deal "shall in no way be deemed an admission of culpability, liability or guilt on behalf of Sally Goldreyer or any of her agents, past or present."

Bharara said Goldreyer "did the right thing" in returning the painting.

The work of American pop art pioneer Roy Lichtenstein, seen at London's Tate Gallery in 1968, continues to command high prices today.The work of American pop art pioneer Roy Lichtenstein, seen at London's Tate Gallery in 1968, continues to command high prices today. (Wesley/Getty Images)