Brown called it a form of "urban terrorism" and offered a $200,000 reward for information that leads to an arrest and conviction.
"It is incredible and even unprecedented for police officers here to be subject to terrorist attack," Brown was quoted in the Times. "We have seen it south of the border but not here yet."
In December, the Gang task force noticed their office was flooded with natural gas in an apparent attempt to cause a deadly explosion, police said.
"It was basically designed so that once somebody came in and moved around a little bit, it would have gone off," said Hemet police Lt. Duane Wisehart. "At the very least, it would have leveled the building and killed whoever was inside."
Wisehart told the Southwest Riverside News Network that there is no doubt the trap was meant for members of the Hemet/San Jacinto Valley Gang Task Force.
Officers arriving for work were saved by their instincts."They were able to recognize right away that something was wrong," Wisehart told the North County Times.
"We are lucky they found what they did," Wisehart said. "Otherwise someone could have been seriously hurt or killed."