Sent_en: 2zh Unconfirmed reports also claim the Federal Security Service was searching for three people ahead of the attack and that the bomber was Vitaly Razdobudko of Stavropol.
Sent_yy: 未经证实的报道还称，联邦安全局在袭击前正在搜寻三个人，爆炸者是斯塔夫罗波尔的维塔利·拉兹多布德科。