Muddy tire tracks, matted weeds and fresh police tape marked an area along La. 415 in West Baton Rouge Parish on Tuesday, outlining the spot where a traveler died and another disappeared during a savage storm that brought the region high winds and a foot of rain. 

The Monday night deluge killed 4, Gov. John Bel Edwards said. Two were motorists caught outside in the nasty weather, one near Port Allen and another at the Bluebonnet Boulevard underpass in Baton Rouge. Search crews returned to the West Baton Rouge Parish scene off-and-on during the day Tuesday but were unable to find one person missing.

Officials said one person died when a 2012 Toyota Venza left La. 415 southbound Monday evening and entered Broussard Bayou, next to a Waffle House at an Interstate 10 entrance ramp. The car's rear bumper remained in the still-engorged drainage canal Tuesday. 

One person was still missing after swimming back to the Venza in a failed effort to save the victim.  

Before stormy weather entered the region again Tuesday afternoon, and at times under sunny skies, the West Baton Rouge Sheriff's Office continued its search for the missing person, deputies peering as best they could into the muddy water.

Sahajda "Doc" Williams, the chief death investigator for the parish coroner, was on the scene surveying the fast-moving water near the culvert. Williams said that while the water level had dropped significantly since the early hours of Tuesday, debris and flood water was making it difficult for investigators to determine where the missing person would have been swept away to. 

The crash occurred when an unidentified driver and two passengers were driving southbound around 9:30 p.m. For reasons still under investigation, the vehicle left the road to the right and entered the flooded canal where it crosses La. 415 just north of I-10, according to the Louisiana State Police. 

The car became submerged and one person, Alvarado Morentes Hermelindo, 40, of Port Allen, died, state police said.

Top stories in Baton Rouge in your inbox

Twice daily we'll send you the day's biggest headlines. Sign up today.

The sheriff's office said three people had been inside the flooded car. Two were initially rescued but one person swam back to the vehicle to look for Hermelindo and never returned, sheriff’s Spokesman Dale Simoneaux said.

The third occupant of the vehicle sustained minor injuries and was treated at the scene, state police said.

The incident remains under investigation, state police said.

The crash comes after a heavy rainstorm caused serious flooding across the area, flooding roadways and stranding cars. West Baton Rouge, East Baton Rouge and surrounding parishes remain under a flash flood watch until noon on Wednesday with an additional 4 to 6 inches of rain expected to fall. 

State police urged Louisianans to use caution when driving over the coming days, particularly after sunset. If drivers approach a submerged road, state police recommend they do not travel through it. 

Staff writer Julia Guilbeau contributed to this report.