The 18-year-old La Trobe University student disappeared while jogging in the One Tree Hill area near Bendigo on Wednesday afternoon.

She was found alone in a Peugeot hatchback in Maiden Gully, 15 kilometres from her usual running route, more than 24 hours later.

It is feared the teenager may have been abducted and held captive.

A 38-year-old man was found nearby and taken into custody, as police cordoned off a crime scene.

Fairfax media understands the man's Kingower home, north-west of Bendigo, was being searched by detectives on Friday afternoon.

He was expected to be charged with multiple offences by 3pm.

Fairfax Media has been told that some of the teen's friends received a text message from her phone, as fears for her safety began to escalate.

The message said the woman was OK, but it did not read like it had been written by her. Her phone was later switched off.

The woman, who studies dentistry at La Trobe University's Bendigo campus, was released from hospital on Friday morning.

Police have requested that her name and image not be published.

Officers were still guarding a stretch of road in Maiden Gully on Friday.

Fairfax Media understands investigators found something linked to the case at the scene, but it is not clear what the item is, or its significance.

Local residents said empty cars were often spotted on Hermitage Road, which is flanked by a winery and houses, set far back from the roadside.

Morris Mayne, who lives near the scene, was confident that he had never seen the Peugeot in the area before.

"I've never seen this car before," he said. "I don't think [the man] lives here at all, it's pretty desolate out here."

He said investigators had been asking neighbours about the car, which he described as gold coloured.

"I'm glad she's safe, that's the main thing. I've got young daughters myself," he said.

The young woman's brother was at her hospital bedside overnight. Her parents are flying home from Europe to be by their daughter's side.

It is understood friends of the young woman raised the alarm after she failed to contact them to let them know she had completed her regular run up One Tree Hill, an area of thick bushland south-east of Bendigo that is popular among runners and cyclists.

The teenager has epilepsy and had established a system with her Bendigo friends, where she would message them at the start and end of her runs, because she had suffered a fit once before.

She sent a Snapchat message to her friends from the top of One Tree Hill, but failed to contact them when she was due to finish her run.

Police mounted a massive search for her, focusing their efforts on several hectares of bushland around the One Tree Hill Lookout.

However, some time on Thursday investigators received a tip-off from a member of the public suggesting the teenager had been seen in a car.

Superintendent Mick West told reporters police were on patrol in a divisional van in Maiden Gully when they spotted a car, the colour of which matched with the tip-off.

"There was a snippet of information that came in that turned out to be very fortuitous," Superintendent West said.

"There were a couple of clues if you like … We were looking for a particular coloured vehicle and the divisional came came across it."

He said the man was found "in very close vicinity" of where the young woman was found. "At the same time ... a male was located in the same area," he said.

The teenager was found in the car on Hermitage Drive about 4.50pm, just as rescuers were about to call off the search for the night.

She was helped into an ambulance, still wearing her jogging gear.

It is not clear where in the car the woman was found, or how and why she was taken to Maiden Gully, an urban area west of Bendigo.

"That will be a matter for investigators to flush out overnight and over the next few days," Superintendent West said on Thursday.

Inspector Michael Talbot, who led the massive search effort, said the teen went for a jog after class.

"She ran up Edwards Road here to the top of One Tree Hill," he told media at the scene on Thursday.

"She sent a photo to her friends indicating that she was here. It's believed she ran further into the hill and down the other side, where she sent some text messages to friends."

While police co-ordinated a 75-strong search team, involving the Air Wing, the dog squad, and dozens of State Emergency Service volunteers, the teenager's friends and family handed flyers out around town and also carried out a sweep of the university campus. Soldiers were also preparing to join the search.

Inspector Talbot said investigators would work to determine how the teen ended up in Maiden Gully, what she saw and who she was with.