We know that Salman Abedi, the Muslim terrorist who perpetrated the Manchester Arena bombing, was a second-generation refugee. His parents were refugees from Libya. While some such refugees were indeed fleeing tyranny. Europe and America all too often took in Islamists who plotted takeovers from European bases. That's why the Muslim Brotherhood and the Ayatollah both operated that way.
US officials are supposedly saying that Abedi went to Libya a few weeks before the attack and came back several days before the attack.
Two obvious issues
1. Major parts of Libya are now controlled by ISIS, Al Qaeda and the Muslim Brotherhood. Anyone traveling there should be flagged.
2. If Salman Abedi traveled to Libya to get training or motivation for the attack, which seems likely, then this is another bloody atrocity (like Benghazi) that is on Obama's dirty hands. His war to empower Islamists in Libya was illegal and widely opposed by the American people. It led to the murder of four Americans, three in Benghazi, and now a number of young girls in Libya.
If anything deserves a special prosecutor, the role of Obama, Hillary and their associates in this illegal war and its horrifying consequences does.