Two people were killed and two others were seriously injured in a head-on crash on State Route 77, also known as Oracle Road, near Oro Valley on Monday, Oct. 26.

The crash happened around 6:15 a.m. in the southbound lanes near Wilds Road at milepost 85, according to the Arizona Department of Public Safety (DPS), as first reported by KGUN9.

DPS said a sedan was traveling northbound on SR-77 when the driver lost control for unknown reasons and hit a traffic signal at Wilds Road. The sedan then crossed a small desert median and traveled the wrong way briefly before colliding head-on with an F-250 pickup pulling a trailer in the southbound lanes.

Both drivers were pronounced dead at the scene. Two passengers in the pickup were taken to a hospital with serious injuries, DPS said.

KGUN9 identified the sedan's driver as Charles Springson III, 38, of Oro Valley, and the truck's driver as Isaac Peraza, 48, of Tucson.

AAA Landscape confirmed one of its employees was killed and two others were injured in the crash, according to KVOA.

In a statement posted to Facebook, the company said the crew was on its way to a job site when a vehicle traveling in the opposite direction lost control and collided with their vehicle.

The company expressed deep grief over the loss, as reported by KOLD, and said it would not release additional details out of respect for the employees and their families.

George Bidwell, a nearby resident, told KGUN9 he started hearing emergency vehicles just after 6 a.m. "Probably a little bit after 6 o'clock, and just sirens after sirens for good half hour," Bidwell said. "Haven't heard that many sirens up here for a long time."

Multiple agencies responded, including the Pima County Sheriff's Department, Golder Ranch Fire District and Oracle Fire, according to Hoodline.

Southbound SR-77 was closed between East Wild Road and East Golder Ranch Drive on Oct. 26 as authorities investigated. Drivers were urged to use North Bowman Road and North Lago del Oro Parkway as alternate routes, Hoodline reported. No official reopening time had been confirmed as of that afternoon.

The investigation is ongoing, according to DPS.