Night of the Living Dandelion by Kate Collins.
Abby Knight is forced to wear crutches to get around, or use a wheelchair when she's indoors. Unfortunately, Abby is known for her clumsiness and manages to wreak havoc either way. Her employees at Bloomers try not to leave her alone in the shop, but sometimes it can't be avoided.
Abby is alone in the shop when a dark, mysterious-looking stranger appears and asks her to procure some unusual plants (such as bloodwort, wolfsbane and srangleweed) for him, claiming he collects them. Then her fiance Marco salvare appears and introduces the man as an old army buddy and his new bartender, Vladimir Serban.
Not only is Vlad tall, with dark hair, he has unusually long canine teeth, dresses primarily in black and has recently left his job as a phlebotomist.
Many of the New Chapel's residents believe he's a vampire, and when a body is found, drained of blood, in the dumpster behind Marco's bar, Vlad is the popular suspect.
Marco is convinced of Vlad's innocence. Abby has her doubts, but trusts Marco's judgement. As they try to prove Vlad's innocence, they somehow manage to find evidence to the contrary. With the readiness of the townspeople (especially the wonderfully comic capers of Abby's cousin Jillian) to believe in Vlad's guilt and otherworldly nature, Collins has skilfully made a significant statement about the bandwagon effect.
Miss Marple was right about human nature!