Corpse on the Porch

Newly-disabled ex-P. I. Candace Sweet's life revolves around recovering from each therapy session in time to go to the next. There's no way she can help her old client, no matter how often the woman calls. Then Mrs. Jarvis shows up on Candace's porch, and both she and Candace's mother are lying in a pool of blood. Several attempts on her own life show Candace the killer isn't finished. The police are stumped, and seem unwilling to help.
Can she push beyond the boundaries of her disability to solve the case before the killer succeeds?