Oregon police issued an arrest warrant for 40-year-old Jessica Smith today after her two-year-old daughter was found dead in their Cannon Beach, Ore. hotel room.

Smith's 13-year-old daughter was discovered by the hotel's housekeeping staff Friday morning with severe injuries and her sister's body—the mother was nowhere to be found.

According to the Oregonian, a medical examiner determined Isabella Smith's death a homicide after an autopsy, although police are still waiting on a toxicology report.

Police Chief Jason Schermerhorn said a news conference Sunday that 13-year-old Alana Smith's injuries—cuts and stab wounds—"were consistent with attempted homicide." Schermerhorn also said that police are still unsure when Isabella died or when Alana was attacked.

KATU reports that the children's father, Greg Smith, is cooperating with police and has been ruled out as a suspect. "There are no other suspects," he told the station. According to the Oregonian, Jessica Smith was under a court order to return Isabella and Alana to Greg Smith that same Friday Isabella was found dead.

Greg Smith had filed for divorce in June. Jessica Smith had apparently left their home in Goldendale, Wash. with the couple's daughters in April. Greg Smith's attorney told the Oregonian that Jessica Smith had recently been ordered to undergo psychological evaluation:

Nathan Petersen, the father's lawyer, said his client had been seeking shared custody of the girls. After Jessica Smith missed a June 23 court hearing, a judge ordered a psychological evaluation and granted Greg Smith visitation with his daughters on Fridays starting in August, Petersen said.

Greg Smith had requested the mental evaluation because he'd received some erratic messages from Jessica Smith that concerned him, Petersen said. On Sunday, police said they did not know if Jessica Smith had psychological issues.

Authorities have launched an expansive search for the mother, with the U.S. Coast Guard conducting aerial searches.

[Image via ABC News/AP]