Backs up when one shouldn't

• Backs up, as a burglar
• Provides inside information for, say
• Helps, as a crook
• Provides tools for, as a crime
• Shills for, say
• Assists in arson, say
• Sticks by, as a stickup man
• Helps a thief
• Sets up crimes

Wiktionary Word definitions in Wiktionary
vb. (en-third-person singular of: abet )