Expert: Need for careful analysis of DNA – ‘Get it right for Hannah’

Investigators are hoping to have the DNA results on the remains found in Butu Road, Valsayn by March 29, but will “take their time” to ensure they get it right.

Newsday understands staff at the Forensic Science Centre in St James believe they are on track to meet the timeline set by the police, but are unable to guarantee anything, given the state of the remains.

On March 12, police searched the compound and found remains they believed to be those of 18-year-old Hannah Mathura, who has not been seen since 2017. The remains were found buried in a shallow grave in the backyard after police were directed there by one of Hannah’s relatives.

Police arrested Hannah’s parents after the remains were found, but released them after a week, on the advice of the Director of Public Prosecutions. Investigators now say the inquiry remains ongoing as they await “specific results” to guide their way forward.

Police told Newsday they are now awaiting DNA tests to determine whether it was Hannah’s body.

A source close to the investigation told Newsday the remains were also taken for x-ray analysis on March 25, with the results expected to be made available to investigators on March 26.

“The evidence was placed in a body bag so the contents remain intact and you don’t lose it and there is no evidence falling off.

“The remains were sent to the Port of Spain General hospital along with contents in the body bag for an x-ray to see if there are any bullets or anything or any other evidence that might be metallic in content.”

According to the source, the DNA tests “will take some time,” given the state of the remains. An expert in the field told Newsday extracting DNA could be a difficult task in this case, as there would be very little bone marrow available for testing.

The scientists doing the tests will have to dissolve the bones to extract DNA.

“When the bones are that old, there’s no skin, there’s nothing in it. The bones are just dried, there’s no marrow, and when they cut those bones they are empty. What you’re looking at is actually trying to extract marrow from the actual bone itself that remains.

“We cut the bone and we try to extract from the inner side of the bone and see what good, reliable DNA results

“You just want to extract the bone and see how much the bone is yielding, and then you can amplify and then get it profiled.”

The expert said this method of DNA extraction is time-consuming and must be done with precision.
“You don’t want to spoil that. You want to do it once and then do it twice to make sure.”

The expert warned that the results are not always favourable and could result in an even longer wait.

“Sometimes it’s hit or a miss…Sometimes you do an extraction and go through the whole test and then you don’t get the result.”

The source said scientists are waiting to see what the first set of results will give before determining if it must be redone.

“A bone extraction is nothing new, and it doesn’t take plenty resources, but it takes time because of how it is.”

The source added investigators and scientists at Forensics are working together as they “want to be sure.

“They are trying to take their time and get a proper extraction.”

The source told Newsday while the public may be eager to see justice served, the focus right now should be on getting the results right.

“Time is very important as well, but we have to be correct.

“This is a real priority case to everybody. Everybody knows this is a priority case. People are aware of it in the media and we really want to try to bring some kind of solution through the use of forensics. So it is imperative not to have errors.”

The source said it is important that the staff at the Forensic Science Centre do not feel pressured into making wrong decisions.

“Just do it correctly, because any (result) will push the case in a direction that is either detrimental to somebody or beneficial to somebody else.”

Investigators hope to compare the DNA sample with samples taken from Hannah’s parents.
The source told Newsday a rushed DNA analysis could also have other implications for the investigation, as gender must also be determined.

“DNA will tell you the gender, that’s why you want to get a good sample. Sometimes, if you don’t do the correct thing, you don’t get a reliable sample, and then the gender could be off. Gender, if it’s male or female, could throw off the entire investigation, if you’re running with the wrong results.”

The source said the case is a priority, with both police and Forensics is treating it accordingly.

“Police working with this case every day. They put in a lot of resources into it. Police and forensics are putting their heads together.

“The Minister (of National Security) is also very attentive in what’s going on and has his mind deep-rooted into this.”

Newsday understands the most experienced specialists at Forensics who have done successful DNA extractions in the past have been assigned to the case and are expected to get results.

The source suggested it was unfair for the public to try to assign blame for the time it was taking to get the results.

The source said despite what is being said, Forensics is more than competent enough to conduct the tests.

“People want to blame the forensic and they don’t have the facts.

“The ultimate goal in this is when you finish and you get through and the family feels a sense of relief. That is the only reward really, to see people relief that they get closure.

"Sometimes, the journey to reach there is a bit challenging, but the police working with Forensics trying to do justice. We want to be fair to everybody.”

Meanwhile, police say they are monitoring the suspects in the case and are aware of their location.

Police told Newsday the possibility of abuse charges being laid against the suspects is also still a consideration, but said the murder investigation is a priority.

“We’re looking at homicide first, and then we’re looking at the abuse of the children, because it will be detailed statements. You have to go into more details, extract that from the children, because, in some instances, there is a lifetime of abuse. We need to be meticulous about that to get all the information.”

Hannah’s siblings have hired lawyers to represent their interests in the case and are said to be assisting police in their investigations.

They have not directly addressed their parents’ arrest or subsequent release last week.
Attorney Sanjiv Boodhu, who spoke on their behalf at a virtual press conference last week, told Newsday he met again with the Mathura children over the weekend but said he had nothing to share with the media or the public “at this time.”