NYPD policemen watch the crowd at a boardwalk.
Policemen watch the boardwalk.
Sentence one just emphasizes that the policemen that are watching the boardwalk are NYPD.
exists e1 x1 x2 x3 x4.(n_crowd(x3) & at(e1,x4) & n_boardwalk(x4) & Theme(e1,x3) & Actor(e1,x1) & v_watch(e1) & n_policeman(x1) & (x1 = x2) & ne_org_nypd(x2))
exists e1 x1 x2.(n_boardwalk(x2) & Theme(e1,x2) & Actor(e1,x1) & v_watch(e1) & n_policeman(x1))