Lawyers for author JK Rowling are investigating a US army magazine cartoon whose characters bear an uncanny resemblance to Harry Potter.
Preventive Maintenance Monthly, which has a circulation of 100,000, teaches soldiers how to care for their kit.
Its cartoon strip includes a boy wizard called Topper and a professor of Mogmart's School called Rumbledore.
A spokesman for Rowling said she has always taken protection of her copyright "very seriously".
But he added: "It's too early to say whether this case is really something to provide us with major concerns."
Among the other similarities in the comic strip are teachers called Snappy and McDonagal. There are characters in the Potter books called Snape and McGonagal.
One of the young female wizards is called Miss Ranger, while Harry Potter's best friend is Hermione Granger.
But the magazine's editor, Ken Crunk, denied there had been any copyright infringement.
"The drawings do not look like any of the characters from Harry Potter," said Mr Crunk.
"We are very careful when we do these things not to copy images because that would be illegal."
In 2003, Rowling halted the sale of a Russian children's book which had a central character called Tanya Grotter, who was a wizard.
The author, Dmitry Yemets, unsuccessfully argued that his book was a parody of Harry Potter.
But Rowling is happy for the popular trend of writing fan fiction online based around her characters to remain, as long as no money is made from it.