Old masters of the classic mystery knew how an enigmatic central character can focus tension and raise the stakes. But Las Piernas News-Express reporter Irene Kelly's latest adventure features a cast of nothing but such enigmas. There's Lucas Monroe, Irene's old sociology teacher, now a street-person who, unrecognized, stumbles across her just days before his sad death in an abandoned high-rise; Dr. Andre Seiman, the brilliant sociologist who got Lucas dismissed for cheating and Irene seduced into membership in the ranks of the SOS (""Survivors of Selman""); Nadine Preston, the grad student who's been missing ever since Lucas's fall from grace back in 1977; Allan Moffett, the Las Piernas city manager who seems to be retiring one step ahead of the lynch mob; and John Jones, a.k.a. Two Toes, the homeless schizophrenic who's appointed himself Irene's guardian angel. All of them are obviously tied to a long-standing land fraud scheme and a rash of suicides. But with the corruption spread as thick as molasses, it's hard to care which of these prize petunias is finally going to end up taking the fall. Too much of a good thing in Irene's fourth case (Dear Irene, 1995, etc.)--a big, ambitious novel that sinks under the weight of its evil cargo.