For the past two months, a pack of thieves has rigged stolen cars and trucks to intentionally ram Las Vegas-area law enforcement vehicles, and police worry the attacks are becoming more dangerous.

According to Metro Deputy Chief Tom Roberts, the group has targeted six police vehicles from three different departments in Las Vegas, Henderson and Boulder City since late April.

"If we don't stop them, they're going to seriously hurt or kill somebody," Roberts said during a press conference attended by the Las Vegas Review-Journal Monday to announce a reward in the case.

In the first incident on April 29, a Bureau of Land Management K-9 vehicle was hit by a van while in the agent's driveway near the intersection of Galleria Drive and Weston Ridge Street about 12:45 a.m., according to police. Since then, five more police vehicles from Las Vegas police and Nevada Highway Patrol have been targeted by the group, Roberts said.

In each incident, Roberts said, the group put something heavy on the vehicle's accelerator, aimed it at a police vehicle and then let it go.

"They have no discrimination on where this vehicle may go, no concerns," Roberts said.

But not every vehicle has hit its mark.

Roberts said a Metro K-9 unit in the driveway of a home was targeted in the early morning hours of July 6, but the stolen truck glanced off the SUV and crashed into a neighbor's car instead.