Edvard Munch's painting The Scream, recently recovered from a 2004 theft, may be too severely damaged to repair, according to a report released Thursday.

Experts at Oslo's Munch Museum are concerned about moisture damage to the iconic painting, they said in report to Norwegian police, who are still investigating the case.

The Scream, shown in a 2003 image from before the theft, has moisture damage, museum experts say.
(Associated Press)

The Scream and another Munch work, Madonna, were ripped from the walls of the museum in front of astonished museum patrons in a daring daylight heist in August 2004.

Police recovered the paintings in last August but have refused to say how they knew where to find them.

In a 200-page assessment of the paintings, turned over to police to help in the investigation, museum experts say they do not yet know if The Scream can be repaired.

"Water has been absorbed by one corner of the paper board, and there is abrasion damage on the lower part of the painting," museum curator Ingebjoerg Ydstie said. "We have a large swath that is very visible."

Experts are still trying to determine what kind of liquid caused the moisture damage.

"When one has further knowledge of the chemical composition one will know whether the damage is going to be stable or whether one may risk the development of further future damage," the museum said in a statement on its website.

Any effort to repair the painting must be cautious because of the possible long-term impact of modern pigments and binding agents with different chemical composition to the original materials used.

"There are types of damage we can't do anything about," museum restoration expert Anne Milnes said in a TV interview.

Munch painted four versions of The Scream, which shows a waif-like figure apparently screaming or hearing a scream.

The other painting, Madonna, was torn in several places and faces extensive repairs.

"The painting will be cleaned, the threads in the tears will be joined one by one and tiny, loose flakes of paint will be carefully fastened to the canvas with the help of a microscope," the museum statement said.

With files from Associated Press