SAN FRANCISCO -- A San Francisco couple whose teenage daughter was allegedly being pimped by a Southern California man tracked him around the state, failing at one attempt to kill him before shooting him to death near Candlestick Park, authorities said Wednesday. Attorneys for the couple say they tried everything to rescue their daughter from Calvin Sneed, a 22-year-old alleged gang member from Compton (Los Angeles County), but that they didn't kill him. Prosecutors, however, say that when Barry Gilton and his longtime girlfriend, Lupe Mercado, couldn't get their 17-year-old daughter back through legitimate means, they turned to premeditated murder....