Time was, all a driver had to do to get away with killing someone with a car in New York City was prove sobriety and stay at the scene. But given the outcome of two recent cases it seems that, at least when the victim is a cyclist, police and prosecutors are flexible on the latter requirement.

It took days for NYPD to track down the driver of a flatbed truck who ran over Mathieu Lefevre in East Williamsburg on October 18. According to Erika Lefevre, who continues to wait for a full account of her son’s death, police said the truck was found two blocks away, and showed visible damage from the collision. She was also told that charges had been dropped against the driver — whose name she still doesn’t know — though she is doubtful charges were ever filed.

A statement from NYPD in today’s Metro seems to confirm her suspicion.

The driver left the scene — cops told Gothamist that he didn’t know he had hit anyone — and no charges have been filed in the case.

“There’s no criminality,” an NYPD spokesman told Metro. “That’s why they call it an accident.”

The NYPD spokesman quoted in the Metro story is not only startlingly insensitive, revealing the department’s casual attitude toward traffic violence, he’s also playing fast and loose in his interpretation of the law. Whatever caused the collision between the driver and Mathieu Lefevre, it is illegal in New York State to leave the scene of a crash.

According to state traffic code, anyone “knowing or having cause to know that personal injury has been caused to another person” due to a collision is required to stop and notify authorities. Leaving the scene of an incident that results in death is a class D felony punishable by a fine of up to $5,000 and up to seven years in jail.

It appears that the decision to file or not file charges in the Lefevre crash hinged on whether the driver knew he struck the victim. According to Erika Lefevre, NYPD says the driver was “likely unaware” of the collision. For a crash that killed someone, this may be a thin reed on which to hang a defense, but it’s apparently enough for police and the office of Brooklyn District Attorney Charles Hynes to consider the case closed.

“The issue of what the driver knew is a critical element of the case,” says Juan Martinez, general counsel for Transportation Alternatives. “If the DA can’t prove that the driver knew he was involved in the crash, the case fails and the driver can’t be convicted of the crime.”

Martinez continues: “So in hit-and-run cases, any driver who claims they didn’t know they killed someone gets a ‘get out of jail free’ card — unless there is a thorough investigation that examines physical evidence, witness statements, etc. Because police have not released the results of their investigation to the family or anyone else, no one knows whether there was a thorough investigation of potentially criminal conduct, or whether they concluded early on that this was an ‘accident’ and simply accepted the driver’s word.”

It is not unheard of for NYPD to pardon drivers after a hit-and-run, even a fatal one. Another notorious instance involved cyclist Marilyn Dershowitz, whose death last July at the hands of a postal truck driver was captured on video. In that case, it was Manhattan DA Cy Vance who initially kept the victim’s loved ones in the dark.

The driver who killed Dershowitz did not stop after the mid-day collision. He later claimed he was unaware he had hit someone. He was not charged.