Detroit police, FBI team up for missing persons search It is a two-day operation called B.L.O.C.K. which stands for Bringing Loved Ones Closer to Kin, and as with many such initiatives involving the feds, they've been pretty tight-lipped about their findings. The Detroit Police Department is teaming up with federal authorities to investigate missing persons cases across the city. The backstory: It's called Operation B.L.O.C.K. — Bring Loved Ones Closer to Kin.