A week after a photographer smashed into Lindsay Lohan's car, police in Los Angeles said they are continuing an investigation into whether the city's notoriously tenacious paparazzi are part of a criminal conspiracy to get photos of stars in stressful situations.

Prosecutors said they opened the investigation months before the Lohan crash, according to a Reuters report, after several incidents where it appeared that photographers collaborated to provoke celebrities in order to get their distressed reactions on film.

"In certain, specific incidents, the paparazzi have crossed the line into criminal behavior," said William Hodgman, of the Los Angeles County district attorney's office. Police said the photographers are frequently banding together to chase celebrities' cars through the city and surround them in traffic, in some cases trying to run them off the road or cause accidents in order to get photos they can sell to the pic-starved weekly celebrity magazines.

"Somebody's going to get hurt or killed because of this activity," Hodgman said. "And we are aware of numerous instances where the children of celebrities have been jeopardized by the conduct of the paparazzi."

On June 1, Lohan called police to complain about being chased by paparazzi. Shortly after, photographer Galo Cesar Ramirez was arrested on suspicion of assault with a deadly weapon after he crashed his minivan into Lohan's Mercedes as she was trying to get away from him. Several other photographers showed up just after the crash to snap pics, but no formal charges have been filed yet in the incident.

In November, Cameron Diaz and Justin Timberlake filed suit against a pair of celebrity photographers, who they said tried to goad the couple into a fight to get a juicy picture. The photographers sued the couple, saying they had been attacked when the duo tried to grab their cameras.

By themselves, many of the traffic violations and other minor crimes the photogs are committing don't carry a big risk, but police said the alleged collaboration between them could bump their actions up to a felony.

"What some people fail to recognize is that if you conspire to commit a misdemeanor, that is, if you are planning those kinds of things out in advance, two or more people, that conspiring to commit a misdemeanor is a felony, and it's a much more serious crime," said police Lt. Paul Vernon. Officials said they are investigating individual photographers as well as agencies that pay for their pictures.

The owner of the photo agency Fame Pictures, Boris Nizon, told The Associated Press he wasn't sweating the probe. "We obey the law and we work really professionally," he said.