A New York man who struck and killed a police officer investigating an accident on the Long Island Expressway broke down in tears at the trial of another driver charged in the officer's death.

The district attorney did not charge Francis Belizaire.

Instead, James Ryan, whom prosecutors say was driving drunk and set off a sequence of crashes that resulted in the officer's death, is on trial.

Belizaire testified he slowed down as he approached a chaotic crash scene in October 2012.

He says he was in the left-hand lane and did not see the wreckage of Ryan's car until the last second. That's when he struck and killed Nassau County Officer James Olivieri.

Later Monday, a defense attorney cited discrepancies in Belizaire's prior grand jury testimony about the crash.