A large number of Islamist students have been arrested in Yemen in the wake of this week's fatal shootings of three American missionaries and the assassination of a socialist political leader, a security official said Thursday. "Many students at Al-Iman University in Sanaa suspected of extremist activities and having links with the assassins of the three American missionaries and the number two of the Yemeni Socialist Party Jarallah Omar were arrested Thursday," said the official, who requested he not be named. He would not disclose exactly how many students had been arrested, but said among them were "persons whose names...