From HiveWiki

Black Van captures weaker attacking hoods in the event of a failed attack against you.

In order to succeed, the hoods in the Black Van must be stronger than the attack (before applying casualties). If this is the case, the weakest hood in the attack will be captured by the defender.

Trapped hoods follow the same rules for rescuing as those kidnapped in a conventional way.

Assets	Requirements
Black Van	Informants size 5

[edit] Trapping Hoods

• The Black Van is ineffective (does not work) against rescue attempts of previously kidnapped (or trapped) hoods.
• If an attack fails, the Black Van will attempt to trap the weakest attacker.
• Trapped hoods, like kidnapped ones, appear in the Streets of the victor.
• Attack value of the Black Van is based solely on the strengths of the hoods stationed there (plus Black Van upgrades)
• The Black Van does not affect rebellions.
• The Black Van does take affect no matter what area (Security Outfit/Lookouts/Harbor Patrol) is attacked.
• Losing a hood to a Black Van does not increase the attacker's alert level.
• Hoods in the Black Van do not participate in the attack, so they do not contribute to the defense rating, and do not take any damage.