Manchester jihadi 'spoke to his nuclear scientist mother, 50, on the phone just before his deadly attack'

  • Salman Abedi's mother, 50, graduated top of her class at Tripoli University
  • Samia Tabbal is also a close friend of the wife of a former Al Qaeda commander
  • Family friend said Salman's parents would be 'very shocked' by bombers actions 
  • It came as six men and one woman have been arrested in connection attack
  • News sources in the US said Abedi's mother was fearful he had been radicalised