A yard in Jamaica, Queens was excavated by police after a convicted murderer said he dumped another body there. Gregory Wynder, who is serving a life sentence for the 2001 murder of a Harlem woman, has claimed he killed two other women--claims that Queens detectives believe are true--in a South Jamaica home where a girlfriend lived. A "handcuffed and shackled" Wynder showed detectives where on the 170th Street (near 105th Avenue) lot he supposedly buried......