Pop artist Roy Lichtenstein's painting “Electric Cord,” which surfaced in a New York City warehouse after being missing for 42 years, was returned Tuesday to the widow of famed American art dealer Leo Castelli.

“More than four decades after it first disappeared, we are delighted to have played a role in securing the return of this painting,” U.S. Attorney Preet Bharara said in a statement, adding that “returning stolen art and artifacts in an important mission of this office, and it is always gratifying when we are successful.”

Lichtenstein’s painting disappeared after Castelli sent it out to be cleaned to art restorer Daniel Goldreyer in January 1970.

Castelli bought the painting sometime in the1960s for $750. The canvas - which depicts an electrical cord tightly wound - is now valued at $4 million.

The Roy Lichtenstein Foundation published an image of the “Electric Cord” on the front of its holiday greeting card in December 2006. In it, the foundation asked for the art community to help find the missing masterpiece.

In July 2012, it had been tracked to the Hayes Storage Facility in New York. The painting had been shipped there from the Quinta Galeria art gallery in Bogota, Colombia, which had received it on consignment from Goldreyer’s widow Sally Goldreyer. 

According to Goldreyer, after her husband passed away in 2009, she began to clean out the lockers of his company’s employees including a man named Ben Dolinsky. She told authorities she gave the contents of Dolinsky’s locker to a “friend,” who asked her three years later to sell the “Electric Cord” painting for him. She says she tried to sell the painting to the Quinta Galeria but refunded the gallery’s deposit when she found a missing notice for the painting posted on the Internet.

In the meantime, Castelli’s widow, Barbara Bertozzi Castelli, was contacted by the Roy Lichtenstein Foundation and told someone was trying to sell her husband’s missing1961 painting.

According to a court filing in New York State Supreme Court, gallery owner James Goodman told the Lichtenstein Foundation he had been contacted by a "third party" and told the painting was at Hayes Storage in Manhattan. He asked the foundation if they could authenticate the painting. He said he didn't realize the painting had been stolen and said that the owners said they had an invoice showing the piece was purchased from Castelli.

Barbara Castelli claimed in court papers earlier this year that she inherited the painting, along with all of her husband’s other artwork and his gallery when he died in 1999. Lichtenstein passed away in 1997.

In July, a court in New York ordered a temporary freeze on the sale of the painting. On Oct. 9, Sally Goldreyer gave up all rights, title and interest in the painting and agreed that it should be returned to Barbara Castelli.