(S (S (BASENP (NNS Police)) (VP (ADVP (RB later)) (VP (VBD confirmed) (SBAR (IN that) (S (BASENP (NN twelve) (NNS people)) (VP (VBD had) (VP (VBN been) (VP (VBN killed) (PP (IN with) (S (S (BASENP (DT a) (RB further) (NN thirteen)) (VP (VBN injured))) (COMMA ,) (S (BASENP (NN three)) (VP (ADVP (RB critically)))))))))))))) (PERIOD .))