WORCESTER – The third week of Mathew Locke’s quadruple murder trial began Monday, with prosecutors beginning to present DNA evidence and a defense attorney pressing a witness about an apparent alternative theory of the crime.

A forensic expert testified about a saliva component she said was detected in the private areas of the mother and daughter found murdered in their home at 10 Old Warren Road, West Brookfield, on February 28, 2018, while a woman who stayed in the house next door that night faced intense scrutiny from the defense.

The woman, Christine Tatro, denied telling her ex-husband that the owner of the house next door left for a long period of time on the night of the crimes, or that he returned smelling of fuel.

Neither the ex-husband nor the neighbor have testified so far in the case. Tatro testified that her relationship with her ex-husband was contentious.

Jury hears start of DNA evidence

Jurors heard Monday morning and afternoon the beginning of what is expected to be the key forensic evidence against Locke.

Prosecutors have said DNA evidence links Locke, 38, to the murders of Sara Bermudez, 38, and her three children: 8-year-old Madison, 6-year-old James and 2-year-old Michael.

Locke is a cousin of Sara Bermudez’s husband, Moses, who was away on work at the time of the murders and testified at the trial.

State police forensic expert Kelley King testified at length Monday about items she analyzed in the master bedroom of the Bermudez home, where authorities found the four victims stabbed repeatedly and burned by fire.

The fire, which they suggested was started by diesel fuel, was not burned, and prosecutors have painstakingly presented dozens of pieces of evidence found in the room.

King tested many of the items, from bloody and burned clothing to a piece of blood-covered rope that was found partially burned at the scene.

As jurors watched silently, she testified about dozens of individual blood stains found on walls, carpet, a lamp and other items.

The central part of his testimony appeared to be a saliva component, called amylase, that he said he found inside and outside the genital areas of Sara and Madison Bermudez.

King, who worked for more than 15 years at the lab, explained to the jury in detail the process he uses to do his job, from sterilization and protective equipment to a simplified explanation of the tests he performed.

King testified that he tested swabs collected from various areas of the mother and daughter’s bodies for semen and saliva.

No semen was found, he testified. He said amylase, an enzyme present in saliva, was found in swabs taken from the internal and external vaginal area of ​​the mother and daughter.

King testified that he prepared samples from them and sent them to the DNA lab for further testing.

During cross-examination, Locke’s attorney, Jeffrey S. Brown, pressed King about his work, as well as the importance of the evidence.

King, after a line of direct questioning, agreed that the test he performed was a “screening” test that did not confirm the presence of saliva, but indicated that it could be present due to the detection of amylase.

He said the samples were sent to a DNA analyst for more conclusive testing. That analyst is expected to testify later this week.

Brown also questioned King about the photographs he took of the positive amylase tests. Projecting them on a screen, she suggested that at least one of the tests did not appear to have a line where she indicated yes.

King said his tests were accurate and were confirmed by others. She acknowledged not taking photographs of some of the evidence she used to reach her conclusions, saying that was allowed by state police policy because another qualified person present certified the results.

Photographs of the evidence were difficult to see clearly from the courtroom gallery.

Contentious cross-examination

In the afternoon, jurors heard from Tatro, a woman who had connections to both the Bermudez family and their immediate neighbor.

Tatro, during her direct examination by prosecutors who called her, said she knew Sara and Moses Bermudez because she had worked for one of Moses’ aunts at Mason’s Grille in Warren.

Tatro testified that he met Sara and Moses Bermudez when they came to the restaurant, and that his children had playdates with Bermudez’s children several times.

Tatro testified on February 28, 2018 that she and her husband were separated and, while living with their children, they saw other people.

He said that at the time he had been seeing a man who lived right next to 10 Old Warren Road, and that he stayed there the night prosecutors accused Locke of killing the family.

Tatro told prosecutors that she and the man she was dating went to bed around 8 p.m., slept through the night and didn’t hear or notice anything peculiar.

During cross-examination, Brown peppered her with questions about different things he claimed she had said to her ex-husband.

Tatro denied a number of questions, including suggestions that she had told her ex-husband that the man she was dating had left the house for a while that night and had returned smelling of fuel.

The timing of her alleged statements to her ex-husband was unclear in the testimony, which was at times tense, contentious and contained references to multiple prior police interviews.

Tatro told prosecutors that her relationship with her ex-husband had been contentious and that she did not trust him at the time of the murders.

Brown, during cross-examination, suggested that Sara Bermudez had emailed Tatro’s ex-husband about Tatro’s relationship with the neighbor, and that the neighbor was angry with Sara Bermudez.

He also asked Tatro if Moisés Bermudez and the neighbor had ever had a physical altercation at Mason’s Grille.

“I have never witnessed anything like this,” Tatro responded.

After Brown’s questioning, prosecutors asked Tatro if she, with her ex-husband’s knowledge, had had sleepovers with her children at the neighbor’s house after the murders; Tatro answered yes.

Tatro also said the neighbor suffered from heart problems and was unable to engage in prolonged physical activity.

Brown, who asked a question that cast skepticism on that claim, will have a chance to call his own witnesses after prosecutors wrap up their case.

The trial is expected to last next week.

This article originally appeared on Telegram & Gazette: Mathew Locke trial: DNA evidence introduced, defense theory emerges