NEW : Police say they ' ve received four calls -- three on Tuesday . A fourth car near mobile home park is searched for clues . Sandra Cantu played with a friend on Wednesday , headed for a second friend 's house . It 's not clear whether she ever got to the second house , family says .
NEW : Police say they 've received 477 tips -- 100 on Tuesday . A fourth car near mobile home park is searched for clues . Sandra Cantu played with one friend on Friday , left for a second friend 's house . It 's not clear whether she ever got to the second house , family says .