She has never received a call from Cambridge police looking for help in tracking down a criminal, but Kate Mattes thinks she's got the know-how to solve a crime from her 50-odd years of reading about them.
Mattes owns Kate's Mystery Books in North Cambridge. And though she has read enough mysteries to find the bad guys, she has no desire to write one.
"You have to sit still for hours, not talking to anyone," she said.
She much prefers talking crime with her customers, who include acclaimed authors Robert B. Parker and Stephen King.
But she's not sure how much longer she'll be chatting up fellow fans and famous writers at her current location. Mattes has put the house in which the bookstore resides up for sale.
"It's a kind of family planning," she said with a laugh. "No one in my family wants to run the bookstore someday or own the house."
So she's capitalizing on what is still a good market and selling the old red Victorian. Its 3,400 square feet include the store, her living space, and a rental apartment and is on the market for $1.325 million.
Mattes said she doesn't plan to sell the business, but is looking for a partner so she can move her 15,000 titles to a larger space and allow the business to continue far into the future.
Ideally, she would like to stay in Cambridge. "I've been very happy here," she said. "I love this neighborhood."
Next Saturday, from 10 a.m. to 3 p.m., she will hold a yard sale offering many of the belongings she has amassed during her nearly 25 years in Cambridge. She'll be peddling linens hand-crocheted by her grandmother, furniture, lamps, and sets of china.
At the end of October, she will hold a book sale and even plans to part with some of her collection of 1,500 black cats - those with pumpkins or white faces and duplicates - that dot the bookstore.
When Mattes moved into the house in December 1982 and began renovation and knocking down walls, she discovered the house had its own mystery, one that remains unsolved.
"Nobody can figure out where the house came from," she said. "There's no record of it being built here."
But she found a letter buried, as tradition dictated, beneath the horsehair plaster in one wall, dated 1864 and written by a man named Henderson. Mattes believes he must have built the house - the letter was addressed to a woman - because he said he was saving his money so she could decorate it.
Mattes also believes he was connected to the Hendersons who owned a carriage business where the nearby Elephant Walk restaurant is now. But according to Mattes's research, in the early 1860s a blacksmith occupied the spot of land where her house perches.
"Maybe there's a connection," she says. "It seems like a no-brainer, but it's still not solved. Charles Sullivan from the Historical Commission thinks it was moved here from somewhere else." But no one knows for sure.
Despite the house's mysterious origins, Mattes didn't want it to become a scary house in the neighborhood when she opened the store in May 1983. But she did want to honor the mystery genre with an opening date of Friday the 13th.
Born in Iowa, she came to Cambridge via New York, where she first worked for a publisher while in college. She made frequent trips to see friends in Cambridge, and when it came time to graduate she was torn between moving to California ("It was the '60s," she said) and moving to Massachusetts. But she had more friends here.
She had always wanted to own a bookstore devoted to mysteries, though there was no such thing during her childhood. She has held on to some of the first mysteries that lured her into the genre, some of which have been put out on the already crowded shelves.
One of the joys of owning an independent bookstore, she said, has been discovering new writers. "I sold Tony Hillerman books five years before he hit the bestseller lists," she said.
"Mysteries are a much broader category than some people think. Some writers don't fit the stereotype and get squeezed out."
But Mattes finds a place for those writers on her shelves. She also stocks books by New England mystery writers including King, Parker, William Tapply, and Jeremiah Healy.
And she's just as happy taking recommendations as she is handing them out, although since she put the house up for sale, the recommendations take another form.
"My customers all want me to relocate to their towns," she said. "I'm hoping they'll find me a good deal."