Imagine taking a bus tour of Pasadena that offers a thorough look at the city’s neighborhoods, ranging from the old Millionaire’s Row mansions along Orange Grove Boulevard to small tract-style abodes in the working-class neighborhoods of East Pasadena. You’re surr-ounded by 50 other people eager to learn about the city, and led by two tour guides who are even more eager to teach them.

This may seem like just another blandly pleasant way to pass the time on a lazy weekend afternoon. But if you’re one of the die-hard and morbidly curious people climbing aboard the Pasadena Confidential Crime Bus tour, you’ll find yourself engaged in a five-hour trip through the strangest murders, accidents and outright mayhem that a century of Pasadena history has to offer.

Adding to the fun of the tour — which will be offered again Sunday — is the fact that the two guides in charge of the trip, Kim Cooper and Nathan Marsak, inject every gruesome detail with a truly wicked wit, ensuring that the overall mood is more incredulous than morbid. And on Sunday, they’ll be including an appearance by Crimebo the Clown, who has joined what Cooper and Marsak have dubbed the 1947project (the year the body of Elizabeth Short, also known as the Black Dahlia, was found sliced in half) in a bizarre fashion: He is available for birthday parties, at which he will cheerily guide guests through a litany of strange deaths that occurred on their birthdays.

But having established themselves as the murder historians of Los Angeles through their highly popular Black Dahlia and Bunker Hill Crime Bus tours, the duo find walking the delicate tightrope between extreme dark and light is a surprisingly nimble enterprise.

“People want to know what’s real, what really happened. There’s kind of a generalized whitewashing of our society, in which buildings get torn down and big skyscrapers and condos go up and make it look like nothing ever happened here,” says Cooper. “We’ve lost our past, and I think people want to find it again. The appeal is that we’re the stick turning over the stones and finding the bug underneath. And people say, ‘Wow, we really do have a colorful history, but we can get it back.’”

Cooper and Marsak started their quest to shine a light on the darkness of our seemingly civilized society as the lead bloggers of the 1947project Web site, an online venture that selected 1947 as a particularly unsettling year in the city’s history and analyzed the crimes and strange deaths that occurred then on a daily basis.

Cooper’s fascination with the dark side of history arose from being a third-generation Angeleno who found crime to be “a window into everyday social interaction of the past.” She is also trained as a historian and an art historian, and while studying art, she found a strong interest in “creepy subject matter” and wrote her master’s thesis on the subject of visceral arts — “blood and guts imagery” — in postwar art.

“I was interested in artists like a man who did installations in meat lockers in New York City and had high society come down and walk through the meat lockers. I also dealt with a lot of Japanese artists who dealt with the aftermath of atomic explosions,” Cooper says. “My theory was that people were interested in visceral arts because they were looking for the soul. Needless to say, I wasn’t too popular in academia because my ideas were extreme, and while I was too disturbing for academia, I’m apparently not so with the general public.”

Indeed, the attendees on the bus tour seemed to be typical citizens who just happened to harbor an unusual curiosity. And their fascination was fulfilled thanks to the 70-plus tales of death and destruction offered along the way, ranging from a stop outside the home of Robert Kennedy’s assassin Sirhan Sirhan to a thorough recounting of a 1926 bleacher tragedy at the Rose Bowl Parade that has been conveniently overlooked on the Rose Parade’s historic timeline, despite the fact that dozens were injured and one person was killed.

Other incidents explored include the tale of Marie Baker, whose bedroom mysteriously exploded, hurtling her through the roof of her home before she landed on the street outside, dead but still attached to her mattress. Then there’s the tale of the 1947 Ives & Warren poisoning, in which a man entered the now-defunct Ives & Warren Mortuary in order to drink poison and die without burdening loved ones with corpse transportation issues. In a bizarre twist, the man was found to have emulated one of the mortuary’s owners, who had also committed suicide on the premises three years before.

Add in the George Judd murder, in which the high-society favorite and mortgage firm vice president was revealed to have lived a double life pursuing random sex and bar fights with “rough trade boys” before being killed in mysterious and brutal fashion. Combine that with the bizarre death by explosion of Jet Propulsion Lab pioneer and rocket scientist Jack Parsons, plus the strange end of cult favorite actor Jack Nance (“Eraserhead”) after a morning donut run, and you’ve got a full afternoon of atrocities.

“There are a lot of weird tours around the world, but I don’t know if anyone’s doing exactly what we’re doing. And you have to realize that the sheer number of odd deaths is due to finding aggregate deaths over time rather than a non-stop crime wave,” says Cooper. “But we want to go a lot deeper and explore things that aren’t in the collective memory, and we stayed up many nights poking around digital archives such as that of the LA Times entering the word Pasadena and words like ‘ghastly,’ ‘grisly,’ ‘bizarre’ and ‘severed.’”

The hard work has paid off for college buddies Marsak and Cooper, who met while in college at UC Santa Cruz. While they are not partners in life — in fact, Marsak introduced Cooper to her husband — they are literal partners in crime, thanks to their tours. And as the word gets out and society continues to offer fresh mayhem for their satisfaction, they hope they’ll find plenty of others who share their fascination.

“When people are involved in a crime, they become noticed by the media and it sort of puts a freeze frame on their lives for that moment, and you can see what it’s like for an ordinary person at a moment in time,” says Cooper. “The criminal history of Los Angeles and Pasadena brings the offbeat everyday world that would otherwise be lost into focus.”