LOS ANGELES (Reuters) - Police in California’s Central Valley have launched a manhunt for at least one suspect after a series of 10 random shootings on vehicles left one woman wounded this holiday season, officials said on Thursday.

A bullit hole in a victim's vehicle window is shown in this photo in Fresno County, California, U.S., provided December 21, 2017. Fresno County Sheriff's Department/Handout via REUTERS

Fresno County Sheriff Margaret Mims has warned the shooting attacks, which have occurred in her jurisdiction and neighboring Madera County, could turn deadly.

“If this keeps going, it’s going to be a matter of time before we have a murder investigation,” Mims said at a news conference. “That’s what we’re trying to avoid.”

Witnesses described the suspect’s vehicle as a dark colored pick-up truck with oversized tires, Mims said. The motive for the shootings is unknown, the Fresno County Sheriff’s Office said in a statement.

A woman was struck by a bullet when she was driving on Dec. 1 in rural Fresno County near the town of Kerman, less than 200 miles (322 km) southeast of San Francisco.

Her injuries were not life-threatening.

In the other nine shootings, which occurred between Nov. 27 and Dec. 17, cars were struck by gunfire but no one was wounded, authorities said. Most of the shootings were in Fresno County, just outside Kerman with its population of 15,000 people.

The drivers of those cars said they heard a bang, as another vehicle passed by, according to the Fresno County Sheriff’s Office.

Investigators are not sure if a single suspect is behind the attacks, or if others may be involved, said Fresno County Sheriff’s Office spokesman Tony Botti.

But Mims, speaking in general terms, addressed a single suspect during her remarks at the news conference.

“To the suspect, this is a cowardly act and we are working very hard to find you,” Mims said. “We will hold you responsible.”

Authorities believe the victims were randomly chosen.

A number of communities in the United States have dealt with random shootings on roadways over the years.

In 2015, 11 vehicles were struck by gunfire and a teenager was lightly wounded, in a series of shootings in the Phoenix area. A landscaper was arrested and charged later that year in connection with the attacks, but defense attorneys called into question ballistics evidence used to charge him.

A judge in 2016 tossed out charges against the landscaper, after prosecutors asked for them to be withdrawn.