The U.S. government is launching an investigation into this week’s school bus crash that left a 5-year-old dead.

The Maine Senate Republican office revealed Thursday morning that the National Transportation Safety Board is looking into the Tuesday morning crash in Standish that left Simon Gonzalez dead.

“I wish the family my heartfelt condolences. This is a difficult time for our community. As a graduate of Bonny Eagle High School, I have witnessed our strength before. We will be strong again through the coming months,” Sen. James Libby, who represents District 22, which includes Standish, said in a statement.

Lori Ann Merrifield, 64, was driving a school bus on North East Road, also known as Route 35, about 7:57 a.m. Tuesday when she allegedly hit the kindergartener, according to the Cumberland County Sheriff’s Office.

Gonzalez died at the scene.

Merrifield, whose identity the police made public Wednesday afternoon, was driving the bus, which has been impounded as evidence, for MSAD 6.

The crash happened just blocks from the Edna Libby Elementary School, where Gonzalez attended classes.

The investigation is ongoing.

The NTSB investigation may take 12 to 18 months, though the agency may release a preliminary report within the next few weeks, according to a statement from the board shared by the state Senate Republican office.

It’s the second fatal school bus crash in Maine in less than a month. On Nov. 21, an RSU 13 school bus driven by 65-year-old Jeffrey Colburn of Camden fatally struck 12-year-old Brayden Callahan while the child was in a crosswalk in Rockland. His parents this week hired the law firm Steve Smith Trial Lawyers. Coburn is no longer employed by the school district.

It’s unclear whether the NTSB is looking into the circumstances of the fatal Rockland crash.