Opening statements were heard Monday in the murder trial of the man accused of driving while intoxicated and killing a recent high school graduate.

Police say Michael Grasing, of Babylon, had a blood alcohol level of almost four times the legal limit when he slammed into an SUV on Montauk Highway back in 2012. The crash killed 18-year-old Brittney Walsh, who had just graduated from Lindenhurst High School.

Prosecutors say Grasing was driving 80 to 100 mph before the crash. He has been charged with second-degree murder.

It's unusual for a prosecutor to seek a murder conviction in a fatal DWI case, but the DA's office says the defendant's alleged actions in this case warrant the tougher charge.

During opening statements, the prosecution spoke about a now-deceased witness who had said he saw Grasing driving 100 mph. The defense, however, attacked that witness's credibility, saying the witness had once been charged with attempted murder himself.

If convicted, Grasing faces 25 years to life behind bars.