Driver convicted of murdering head teacher after dragging him under car

• Simon Richardson has been convicted of murdering Michael Mullins, a head teacher.
• Richardson dragged Mullins under his car for over a mile in Manchester.
• The incident occurred on 20 April, as Mullins was traveling home from Stretford grammar school.
• Richardson will be sentenced on Monday.
• The jury heard that Richardson knew Mullins was under his car as he continued to drive.