[Lion Den Dan]

The information make my blood boil but so does this incompetent writing: In December 2010, the group of agent’s was patrolling an area...

..."agent's," (singular posessive) should be "agents," plural.

"was" patrolling should be "were" patrolling. "were" is of course use with the plural "agents."

[Seven_0]

"was" patrolling should be "were" patrolling. "were" is of course use with the plural "agents."

Agents is part of a prepositional phrase. Group is singular, therefore "was" is correct.