MANCHESTER, England (AP) — British police investigating the Manchester Arena bombing have arrested a ninth man while continuing to search addresses associated with the bomber who killed 22 people. Eight other men are in custody in connection with Monday’s blast, with police and security agencies working to prevent further attacks. Britain’s security level has been upgraded to “critical” meaning officials believe another attack may be imminent. Authorities are chasing possible links between the bomber, Salman Abedi, and militants in Manchester, elsewhere in Europe, and in North Africa and the Middle East. Abedi, a college dropout who had grown up in...