Ashley Neufeld of Brandon, Man., and two other North Dakota college students were reported missing Sunday. ((Dickinson State University))

A dive team found nothing Tuesday during a search of a North Dakota lake for signs of three missing college softball players, police said.

Dickinson Police Lt. Dave Wallace said that a search of a nearby youth fishing area also revealed no trace of the Dickinson State University students — a young woman from Brandon, Man., and her two female college mates.

Ashley Neufeld, a 21-year-old psychology student from Brandon, Kyrstin Gemar, 22, of Grossmont, Calif., and Afton Williamson, 20, of Lake Elsinore, Calif., are all members of Dickinson State College's softball team.

They went missing while driving in southwestern North Dakota on Sunday.

Searchers scoured the area from the ground and air on Monday until it became too dark. The search resumed at first light on Tuesday.

The women were believed to have been driving a white 1997 Jeep Cherokee with California plates when they reportedly made a late-night phone call to a friend on Sunday night in which they asked for help before the line cut out.

Wallace said a friend received two telephone calls from them, one minute apart, before the line cut out. Police did not release what was said in those calls, but the friend reported that the women appeared frantic and mentioned water.

Air search to resume

"Someplace in that conversation, water was mentioned. What that context is, is speculation," Wallace said Monday night.

Authorities used three airplanes and officers on the ground to search the region within a 50-kilometre radius of the cellphone tower north of Dickinson, N.D., where the call came through. The search includes Lake Patterson, which is about 157 kilometres west of Bismarck.

Lenny Gemar, the father of Kyrstin Gemar, said the girls often went stargazing in southwestern North Dakota. He told ABC's Good Morning America in a telephone interview on Tuesday that they would hang out by Patterson Lake.

'They haven't found anything that I'm aware of. No tire tracks, no clothing … nothing at all to give us any indication where the girls ended up.' — Lenny Gemar, father of Kyrstin Gemar

Wallace said relatives of the three women have been contacted and are expected in Dickinson by Tuesday. He refused to speculate on what may have happened and said nothing has been ruled out.

"Right now, we just have three missing young ladies," he said.

However, the sheriff's office in Dickinson has said foul play is not suspected.

Gemar said he and his wife arrived in North Dakota late Monday night and were met at the airport by a university official and updated on the case and investigators' efforts.

"They haven't found anything that I'm aware of," he said. "No tire tracks, no clothing … nothing at all to give us any indication where the girls ended up."

Gemar said he had not spoken with the friend who said she received the distress calls, but it didn't seem like the women were being attacked.

"There was nothing to indicate that there was an assailant or anything like that going on," he said. "It just comes across as sounding more like an accident of some kind."

No clue about women's whereabouts

Donnell Preskey, assistant news director at KXMB TV in Bismarck, said many resources are being used in the search, including local and state police, highway patrol and air patrol.

"It's such a large area; they don't have a clue where these girls are," she said. "They're searching pretty much the whole southwestern corner of North Dakota because they don't know how far the girls went.

"They're searching from every direction from Dickinson, north, south, east, west. The phone call was traced to a tower five miles [eight kilometres] northwest of Dickinson, but that phone call could have come in from 30 miles [48 km] out of the town."

"It's scary. It's just a numbing feeling that you have for those kids. There's just so many questions — you're almost speechless because you don't know much," said Dickinson State softball coach Guy Fridley.

Police said they have searched the women's rooms and were interviewing their classmates, friends as well as people near Killdeer, about 56 kilometres north of Dickinson. Investigators are following reports the women and the car may have been seen in that city.

With files from The Associated Press