Detective Acting Inspector Julian Horan, of the Missing Persons Squad, said police had refocused their investigations in light of new information received earlier this year.

"As a result of this new information investigators have renewed a number of lines of inquiry into a person previously spoken to by police," he said.

"The information is promising however sadly leads us to look at the possibility that Krystal met with foul play because of the intimate relationship she shared with a man."

Krystal was days away from delivering her first child - a son - when she was last seen on June 20, 2009.

Detective Inspector Horan said the aforementioned relationship and the subsequent pregnancy might have caused a confrontation between Krystal and the man, leading to her disappearance and death.

"There were a number of people spoken to by police at the time; however this new information has allowed us to narrow our focus more closely on one individual," the detective said.

Police have upped a $100,000 reward, offered in June 2012, to $1 million in the hope of encouraging someone to come forward with information.

Detectives said a 40-second phone call Krystal received on her mobile phone on the night she vanished was important to their investigations.

"We know it was from a public phone booth outside the Leitchville Post Office in Findlay Avenue at 11.59pm, on 20 June, 2009," Detective Inspector Horan said.

"We also know Krystal's phone last showed activity on a Leitchville phone tower at 2.49am, nearly three hours after she received the call from the phone box.

"This indicates to us that the phone was in the Leitchville or surrounding area."

Leitchville is 27 kilometres from Pyramid Hill and about 10 minutes from Cohuna.

Detective Inspector Horan said the proximity to Cohuna was considered important because Krystal had told several people she intended to go to a party in the northern Victorian town the night she disappeared.

"We believe she discharged herself from hospital on the night of her disappearance, against medical advice, because of what she described as a 'party at Cohuna'," he said.

"What we don't know is, whether or not there was actually a party, if there was - who attended and what was the specific location?"

Krystal had intended to give birth at Bendigo Health.

Police said hospital staff were among those Krystal had told about her plans to attend a party in Cohuna the night she disappeared.

"Calls to Krystal's mobile phone, from the Leitchville phone booth, the night prior to her disappearance and while she was at the hospital; lead us to believe they relate to the 'party' she mentioned to hospital staff," Detective Inspector Horan said.

"Investigators strongly believe that the caller was the last person to speak to Krystal prior to her disappearance.

"I believe this caller holds the answers to what happened to Krystal and may be the father of Krystal's unborn child."

Police have not been able to locate Krystal's mobile phone.

One of the heavily pregnant woman's last known movements was travelling from Bendigo to Pyramid Hill on a V/Line train.

Detectives established that Krystal got off the train at the Pyramid Hill Railway Station about 8.40pm the night she vanished.

She was last seen alive leaving an address in Albert Street, Pyramid Hill, about 9.30pm, after vising an acquaintance.

Police said Krystal had been wearing an orange top, black tracksuit pants and a camouflage-patterned baseball cap.

A flyer posted on the windows of several businesses in Pyramid Hill in 2009 said Krystal had a deep voice and was streetwise, friendly and trusting. The flyer said Krystal had epilepsy and asthma.

She also lived with a mild, undiagonsed intellectual disability - the result of bleeding on her brain at birth.

Krystal was well known in the Pyramid Hill community. She was described as 167 centimetres tall, with short brown hair and crooked teeth.

Police in 2009 believed Krystal had been to a hairdresser in Pyramid Hill the day before she went missing.

She was known to have spent a large proportion of her time browsing the internet and rarely strayed far from her phone.

Investigators believe Krystal was murdered. But her remains have never been recovered.

Police in 2012 said Krystal's disappearance was "completely out of character".

"She would talk two or three times a day to her family via text or phone," the lead investigator at the time, Detective Sergeant Wayne Woltsche, said.

"And she didn't have any means or mechanisms to just disappear."

Homicide squad detectives and as many as 40 volunteers searched a property about 10km east of Pyramid Hill in October 2009 after receiving two tip-offs about the likely location of Krystal's body.

A 61-year-old Pyramid Hill man was arrested at Pyramid Hill last year, interviewed by police and released pending further inquiries. Police confirmed within months the man was no longer a person of interest.

The case was referred to the Coroners Court.

Detective Inspector Horan said it was unimaginable to try and understand what Krystal's family must have lived through in the past 10 years.

"After all this time it would be some consolation to be able to provide answers to Krystal's family let alone justice for them and Krystal in holding someone to account," he said.

Police said a reward would be paid at the discretion of the Chief Commissioner, "for information leading to the apprehension and subsequent conviction of the person or persons responsible for the death of Krystal".

The Director of Public Prosecutions might also consider granting any person who provided information about the identity of the principal offender or offenders indemnification from prosecution.

Applicants would have to sign a deed of confidentiality to receive the money.

Detective Inspector Horan urged anyone with information to contact Crime Stoppers on 1800 333 000 or visit www.crimestoppers.com.au

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