Police are still investigating the accident that killed a driver on Tuesday.

Flickr - NSW Emergency Vehicles

WAKEFIELD, N.H. (AP) — Police in New Hampshire say four on-duty Secret Service agents have been involved in a head-on collision that killed the driver of the other car.

The accident happened at about 7 p.m. Tuesday in Wakefield, near the Maine state line.

Police said the agents were passengers in a Ford Taurus heading south on Route 16. A northbound Mercury Sable with three people crossed over the center line and collided head-on into the Taurus.

The Sable driver, 45-year-old Bruce Danforth, died at the scene. The agents and passengers in the other car were taken to hospitals with injuries. Their conditions weren't immediately known.

Police are investigating.

It wasn't immediately known in what capacity the agents were working, but Democratic presidential candidate Hillary Clinton was campaigning in a town hall meeting Tuesday night in Berlin, north of Wakefield.

Clinton released a statement about the crash Wednesday afternoon:

"I was saddened and concerned to hear about the serious accident that occurred last night in New Hampshire in which four Secret Service agents were injured and a passenger in a second car killed. My husband and I send our prayers and condolences to all the victims and their families. We are grateful everyday for the service, dedication, and professionalism of the U.S. Secret Service."