From left: Kyrstin Gemar, 22, of Grossmont, Calif., Ashley Neufeld, 21, of Brandon, Man., and Afton Williamson, 20, of Lake Elsinore, Calif. were killed when their SUV plunged into a pond in North Dakota on Nov. 3. (Dickinson State University/Associated Press)

Three college softball players who drowned when their sport utility vehicle went into a livestock pond in southwestern North Dakota had not been drinking or using drugs, final autopsy results show.

Lt. Rod Banyai of the Dickinson, N.D., police department said toxicology tests came back negative for Ashley Neufeld, 21, Kyrstin Gemar, 22, and Afton Williamson, 20.

The bodies of the three Dickinson State University students were found Nov. 3 inside Gemar's SUV, which was submerged in about three metres of water in a pond about 15 kilometres northwest of Dickinson.

The body of Neufeld's dog was also found in the vehicle.

The women were believed to have gone on a stargazing trip two nights earlier. Authorities said they likely drove straight into the water in the darkness.

Neufeld was from Brandon, Man., while Gemar and Williamson were from California.