Trisha Graf was last seen driving in Andamooka, Australia, at around 2:00 a.m. on Dec. 12

Police have declared the disappearance of 41-year-old Trisha Graf from Andamooka a major crime.
Trisha Graf.Credit : South Australia Police

The disappearance of an Australian woman has been declared a “major crime.”

On Tuesday, Jan.6, the South Australia Police confirmed in a press release that 41‑year‑old Trisha Graf was last seen driving along Dunstan Drive, Andamooka — a remote town 385 miles north of Adelaide — at around 2:00 a.m. on Dec. 12.

“Following just over three weeks of intensive investigations and extensive ground and air searches, detectives believe Trisha’s disappearance is suspicious,” the release read.

Authorities added, “Trisha was at the Roxby Downs hotel at 12.19 a.m. on Friday, 12 December. She left a short time later and was driving a white 2012 Ford Territory, SA registration S254BCX, accompanied by a friend.”

Graf — who is a mother-of-two, according to news.com.au, 9News, and Australian news outlet The Nightly — collided with a kangaroo after leaving the hotel and driving from Roxby Downs to Andamooka, police said.

The collision occurred near the Andamooka Township, authorities revealed in the release.

PEOPLE has contacted the South Australia Police and Roxby Downs Hotel for further information but did not immediately receive a response.

Police have declared the disappearance of 41-year-old Trisha Graf from Andamooka a major crime.

Trisha Graf vehicle near the Blue Dam east of Andamooka.South Australia Police

“After striking the kangaroo Trisha and her friend continued onto Andamooka where they visited a home in the north-western area of the town,” the release continued. “After a short time Trisha left just before 2am to travel the short distance home. Trisha was last seen driving along Dunstan Drive, Andamooka.”

Graf’s partner and friend went on to look for her at around midday on Dec. 12, before locating the missing woman’s “Ford Territory, which was perched on a dirt mound near the Blue Dam east of Andamooka.”

“The vehicle had accident damage caused by the collision with the kangaroo [and] was unable to be driven because of its location on the dirt mound,” police said.

Police and State Emergency Service carried out an initial ground and aerial search in the area for Graf.

Police have declared the disappearance of 41-year-old Trisha Graf from Andamooka a major crime.

Trisha Graf vehicle near the Blue Dam east of Andamooka.South Australia Police

Members of the Andamooka community then searched with Police divers also assisting in the operation.

According to the release, Detective Superintendent Darren Fielke, Major Crime Investigation Branch officer-in-charge, said authorities have grave concerns over Graf’s welfare.

“Since Trisha was last seen there have been significant investigations and several detailed, thorough searches conducted in an effort to locate her,’’ Det. Superintendent Fielke said.

“Her thongs [sandals] were found with her vehicle and we would have expected to locate her if she had simply wandered off a short distance,” he added. “Taking this step in the investigation will allow more specialist resources to be committed to both determine what has happened to Trisha and locate her.’’

“We are still seeking information from people who were with Trisha at the Roxby Downs Hotel shortly before her disappearance and those who saw her after she returned to Andamooka,’’ Fielke concluded.