Murder Ink, a beloved Upper West Side bookstore on Broadway between 92nd and 93rd streets, which describes itself as “the world’s oldest mystery bookstore,” is closing December 31. Its companion store, Ivy’s Books, is shuttering as well. “We just can’t keep up with the rent on Broadway anymore,” said Jay Pearsall, who has been an owner for 17 years.

“The store is a landmark, because it was the very first in America that specialized in mystery fiction,” said the owner of Mysterious Bookshop and a New York Sun columnist, Otto Penzler. “It’s indicative of the fate that is befalling independent bookstores across the country.”

An owner of the West Village mystery bookstore Partners & Crime, Kiz Reeves, said she was very sorry to hear of its closing. Murder Ink, she said, “inspired the rest of us to follow.”

Dilys Winn, who wrote a novel titled “Murder Ink,” founded the shop in 1972 and owned it for 3 years. Carol Brener was owner for the next 14 years. She published a sought-after, single-spaced newsletter. In 1980, the store spawned a short-lived television show called “Murder Ink,” starring Tovah Feldshuh.

An employee who later was the editor-in-chief of the Mystery Guild, Jane Dentinger, began working there in the early 1980s when it was in a small space on West 87th between Broadway and West End. The landlord was a next-door parking garage, where the rest room was located.

The present store has a wire-haired pointer named Gus. Ms. Dentinger recalled the earlier store had two pets: a black and white tuxedo cat named Clouseau and a Maine coon cat named Humbleby, which would jump on her back in the storeroom. Ms. Dentinger would emerge from the storeroom wearing the cat like a fur collar.

The co-owner of an Upper East Side mystery store, Black Orchid Bookshop, Bonnie Claeson, said the staff at Murder Ink was “always knowledgeable about mysteries, new and old.”