A forensic scientist with the Massachusetts State Police Crime Lab took the stand Monday afternoon in Brian Walshe’s murder trial, further laying out for the jury the physical evidence recovered in the days after Walshe reported his wife missing that showed she was not missing, but dead.
The scientist, Matthew Sheehan, found and tested several stains that appeared to be blood inside the Walshe home, as well as several items recovered from a trash bag in a Swampscott dumpster near where Walshe’s mother lived.
Among those items were a hacksaw, a hatchet and a hammer, which were all confirmed as having blood on them.
Sheehan first became involved with the case on Jan. 8, 2023, a week after Walshe reported his wife missing. On that day, he went to the home at 516 Chief Justice Cushing Highway in Cohasset, where Brian and Ana Walshe were living with their three children.
During his search, Sheehan said he found a knife stashed in a kitchen cabinet that screened positive for the presence of blood. Jurors were shown a photo of the kitchen knife.
Sheehan then described his search of the basement, where, in a back corner, he found several stains that appeared to be blood. The stains were purple, he explained, because of a chemical used by investigators to detect blood.
Five stains in a back corner of the basement all screened positive for the presence of blood. Sheehan explained that he collected swabs of the stains to undergo further testing.
Sheehan also found what were later determined to be blood stains on a broken step down into the basement and on the support beam beneath the stairwell. He later tested both second-floor bathrooms, where the sinks and showers all screened negative for blood.
The next day, Jan. 9, Sheehan returned to the home for more testing — he told jurors it was rare for him to visit a scene more than once.
That day, he examined the front, left bedroom inside the home, where he noticed red-brown stains on a window curtain, white residue on the wood floor and an area where the varnish appeared to have been removed. But all three areas he marked screened negative for blood.
On Jan. 9, Sheehan returned to the basement, where he discovered another stain that would screen positive for blood. The stain was in an area of the basement near bright blue Lowe’s buckets — jurors saw surveillance video of Walshe buying similar buckets on Jan. 1.
Sheehan then performed confirmatory tests on the stains at the crime lab. He told jurors the process was akin to a pregnancy test.
While not all the stains from the home were confirmed to be blood, Sheehan said he preserved them for further DNA testing.
At the crime lab, Sheehan also performed tests on items recovered from trash bags taken out of the Swampscott dumpster near Walshe’s mother’s home. That included towels, cut-up rugs, a plastic painter’s sheet, a Tyvek suit, slippers, a hatchet, a hacksaw, a hammer and a pair of snips.
In addition to blood, Sheehan found a “greasy, oil-like substance” on the hatchet head.
“In my experience, whenever a cutting incident is used on an individual, it can leave behind a greasy, oily substance which is indicative of fatty tissues,” he said.
Prosecutor Anne Yas published photos of each item on the in-court screens for the jury as Sheehan testified Monday.
But for some of the stains, such as the one found on the kitchen knife, Sheehan performed no tests at the lab, instead opting to preserve the sample for DNA testing. He explained he did so because he believed there may not have been enough material to serve both purposes.
That also applied to blood stains found in Walshe’s Volvo, which were sent for DNA testing.
Sheehan did not testify about the results of DNA testing, meaning prosecutors are likely to call another witness who will do so.
Defense attorney Larry Tipton began, but did not finish, his cross-examination of Sheehan on Monday. Much of Tipton’s questions focused on what Sheehan didn’t find.
Tipton noted that investigators decided to tear up part of the floor in the bedroom where Sheehan found the white residue, but found no evidence of biological material there.
“There is nothing in the examination of that bedroom that indicates that any biological substance whatsoever had been deposited on the floor, is there?” Tipton asked.
“Yes, that is correct,” Sheehan replied.
The same was true for the bathrooms, Tipton noted.
“So now, we move to the second floor, the bedroom with the hole in the ceiling, the two bathrooms upstairs, all the way down the stairs and right past, as we can think about that now, so far, we haven’t found anything whatsoever forensically, in that home for those areas?” Tipton asked. Sheehan said he was correct.
Tipton concluded his cross-examination there for the day, and will resume his questioning Tuesday morning.
Brian Walshe is accused of killing Ana Walshe inside their Cohasset home in the early morning of Jan. 1, 2023, then dismembering her body and disposing of her remains at dumpsters across the state.
Before the trial started, Walshe pleaded guilty to two charges, admitting that he moved his wife’s body and misled the police investigation into her disappearance.
During opening statements, his defense claimed Ana Walshe died a sudden, unexplained death.
