A teen driver who caused a deadly chain-reaction crash Tuesday that killed a prominent marine scientist on Lakeville Highway in Petaluma had no driver’s license at the time of the collision, police said Wednesday.

Javier Rodriguez Lopez, 19, of Pittsburg in Contra Costa County told police he failed a driver’s test in 2017 but drove anyway, often taking turns behind the wheel with his father, Jguadalupe Rodriguezsolis, 50, as the pair traveled to and from work, according to Petaluma Police Lt. Ron Klein.

Lopez told officers he had no memory of the moments before the collision and couldn’t say why he drove the Silverado into oncoming traffic, Klein said. When asked if he had been using his cellphone, Lopez said no. Officers will examine Lopez’s cellphone to determine whether he was using it at the time, officials said.

“He went over double yellow lines (and drove into oncoming traffic) — that’s the cause of the collision,” Klein said. “Why he did that? We may never know.”

Marine scientist Susan Williams with the Bodega Marine Laboratory was driving from her home in Bodega Bay to teach a university class at UC Davis when she was killed in the 7:15 a.m. collision on Lakeville Highway near the South McDowell Extension. Lopez, his father and a fourth motorist, who wasn’t identified, were hospitalized with serious but not life-threatening injuries.

Klein said officers believe Lopez was sober at the time of the crash.

Lopez and his father had set out earlier that morning from their home in Pittsburg and were headed to a job in Sonoma County, said Klein, who didn’t know what the men did for work. Lopez told officers he had stayed up until 1 a.m. and was tired, according to police.

Still, Lopez drove with his father in the passenger seat.

The westbound Silverado veered across the double yellow lines and straight into oncoming traffic, sideswiping a truck and crashing into an SUV, sending it spinning across the road and into a field, according to witness reports. The pickup crashed head-on with Williams’ Toyota Prius.

The speed limit in the area is 45 mph, and with a high number of vehicles traveling in the opposite direction, the crash mangled vehicles and sent debris along a broad area of the roadway and an adjacent field, Klein said.

The extensive damage may make it impossible for investigators to determine precisely how fast any of the vehicles was traveling, Klein said. But they will try, and are entering measurements into a computer system to help determine the sequence and dynamics of the crash.

“There are a lot of things that could have happened (to cause the crash),” Klein said.

“At the end of the day, he didn’t keep control of the vehicle and keep it on the right side of the double yellow line.”