Possible Clues:

• One who makes a slip of the pen?
• English witness wants capture of top person who's got away
• One who flew the coop
• One who breaks out of prison
• Fugitive who, phonetically, is 'hiding' in certain letters in 17-, 21-, 52- and 61-Across
• European notice about top fugitive?
• Fugitive better protected by witness after heading for Egypt
• S/he breaks out of prison
• Fugitive taking cover inside English diocese
• The one who got away?