Ms Barnett's handbag was found near the remains of Mr Martinez.
By William Rollo - ABC
Police have found no trace of a central Queensland woman missing for two years and suspected murdered despite extensive searches over the weekend.
Officers investigating the disappearance of Chantal Barnett and Robert Martinez were called to a property on Saturday at Parkhurst on Rockhampton's north side after a tip-off.
Ms Barnett, 27, and her partner Mr Martinez, 26, were last seen alive in March 2013 around the Rockhampton and Yeppoon areas.
Late last year, human remains found on a 6,000 acre-property at Rockhampton were confirmed to be those of Mr Martinez.
Detective senior sergeant Scott Moon said investigators were continuing to receive information.
"There are members of the community out there and in recent times it has been shown that loyalties break," he said.
"People will come forward and they're providing us with vital information and we're very thankful for that.
"We know there are other witnesses out there that may be loyal to the perpetrators of this violent crime and we call on them to look inside themselves.
"You have a conscience — come forward, give us the information."
Detective senior sergeant Moon said a $250,000 reward is still being offered to anyone who helps solve the case.
"Do not be afraid to come forward. We will assess that information and we'll assist you as much as we can to ensure that you feel safe in providing that information and rest assured, we will act on it," he said.
A handbag containing items belonging to Ms Barnett was found at the same property where Mr Martinez's remains were uncovered.
Updated
Two men charged over the deaths of Chantal Barnett and Robert Martinez in central Queensland have been remanded in custody.
Ian Robert Armstrong, 31, and Daniel George Hong, 41, appeared briefly in the Rockhampton Magistrates Court this afternoon on two counts of murder.
Mr Martinez, 26, and his partner Ms Barnett, 27, were last seen alive in March 2013 around the Rockhampton and Yeppoon areas.
In October 2014, human remains found on a 6,000-acre property at Rockhampton were confirmed to be those of Mr Martinez.
A handbag containing items belonging to Ms Barnett was found at the same property where Mr Martinez's remains were uncovered.
Ms Barnett's body has not been found.
Police said the arrests were the result of an extensive three-year investigation conducted by the Rockhampton CIB and homicide detectives.
Officers said the investigation had also received significant input and support from Queensland's Crime and Corruption Commission.
However, police said officers were still seeking information from the community as the investigation continued.
Armstrong and Hong will return to court in April.
Last month, Mr Martinez's mother Julie told the ABC that detectives investigating the deaths had narrowed their list of suspects.
"They've told us many times that they're pretty sure they know who the suspects are and who they're looking at," she said.
"It's just getting that bit more information out, so they can go ahead and start arresting the people involved, the perpetrators."
Ms Martinez said both her son and Ms Barnett had previously been ice users and that drugs may have played a factor in their deaths.
She also said she believed there were people who knew what happened to them who had not come forward.
"There's a lot of people out there who know. You walk around and you see some of these people and you know they know, you know they haven't said anything.
"They look at you and it's really hard not to walk up to them and just want to shake them and say, 'What's wrong with you? Where's your morals, where's your decency? If this was your family, I'm sure it would be a different story - you'd want people to speak up'."
By Emilia Terzon and staff - ABC
A father is seeking answers after murder charges relating to his daughter's death were dropped in a central Queensland court.
Chantal Barnett, 27, and her associate Robert Martinez, 26, were last seen alive around Rockhampton in 2013.
Last week, two men went on trial in the Supreme Court in Rockhampton for murdering the pair and interfering with their dead bodies.
The trial of Robert Armstrong, 33, and Daniel George Hong, 43, was initially described by the prosecution as one that would "expose Rockhampton's seedy underbelly".
But in a surprise move midway through the trial, Mr Hong and Mr Armstrong pleaded guilty to two counts each of interfering with a corpse.
The two murder charges, to which the pair had pleaded not guilty last week, were then dismissed.
Outside court on Tuesday, Glen Barnett said he had been left with no answers about the death of his daughter.
"There's a big hole. A big hole missing in our life," he said.
Mr Martinez's body was found in bushland near Rockhampton in 2014 and Ms Barnett's handbag was found nearby.
Ms Barnett is presumed dead but her body has never been found.
During sentencing on the remaining charges, Justice Graeme Crow said he was "troubled deeply" that Ms Barnett's body had never been located.
He asked Mr Hong and Mr Armstrong to put themselves in the shoes of the deceased duo's families.
"You've been asked to cooperate and you've refused to do so.
"You have the right to silence. You don't have to cooperate. But if there's any modicum of decency in either of you, at some point, you will cooperate. You can't be punished any further. There's no downside."
Justice Crow sentenced Mr Hong and Mr Armstrong to two years and 378 days in prison, respectively, for the two charges of interfering with a corpse.
After time served on remand in the lead-up to the trial, both men walked free.
Both men avoided the media by leaving court through a back door, and neither defence nor prosecution lawyers would comment on the outcome of the trial.
Mr Barnett said the only thing they could do now was get on with their lives.
"We've just lost. We've lost," he said.
In the first days of the trial, the court heard that both the accused and their alleged victims were all users of the drug ice, and that Ms Barnett was trying to get cash from pawnbrokers to pay back a large drug debt before she disappeared.
Ms Barnett's friend told the court she had received death threats and was fearful for her life.
Other witnesses gave evidence about conversations they had with the accused or overheard about them disposing of bodies.
But throughout the trial, both of the accused's lawyers argued that the case was based on rumours, and that rumours did not amount to fact.
Crown prosecutor Vicki Loury had told the court the circumstances in which Ms Barnett and Mr Martinez died "were unknown".
"However they have come to lose their lives, they've been disposed of at the same time in the same area," she said.