Tom Cavanagh (Love Monkey, if you will) has been cast as Sheriff David Reichert, the lead investigator on the trail of the worst serial slayer America has seen, in Desperate: The Search for the Green River Killer, a Lifetime mini based on Reichert's true-crime book Chasing the Devil. Also on board are Amy Davidson (8 Simple Rules) and Sharon Lawrence.... Lifetime has also greenlit Matters of Life & Dating, a TV-movie starring Ricki Lake as a woman who resumes dating after surviving breast cancer. Holly Robinson Peete also stars. The pic bows Oct. 22, during Breast Cancer Awareness month.For truly Desperate (as in Housewives) casting news, see the Ausiello Report.