The man reportedly told police he was planning a painting project.
He said he bought some of the items earlier that day, Feb. 12.
Detectives say the material from those coveralls matches patterns left in blood at the crime scene, according to investigative documents obtained by The Herald.
Susann Smith, 37, was beaten to death. Police found her body inside her home after she didn't show up for work.
In the weeks since, Bothell police have centered their investigation around Smith's estranged husband. The couple were going through an ugly divorce and were in a custody battle over their two young children, court papers show.
They lived separately. Police have searched both homes for potential evidence.
The Herald is not naming the man because he has not been charged with a crime.
No arrests have been made, Bothell police Sgt. Ken Seuberlich said Friday. Additional forensic tests are planned.
"They're just continuing the investigation and following up on leads," he said.
Detectives have collected genetic samples from Smith's husband to compare to the evidence recovered at the scene, records show. They took photos of his hands and other parts of his body to document any injuries. They used special lighting that can reveal bruising not otherwise visible.
Police have since determined that an axe found at Susann Smith's home likely isn't connected to the killing, Seuberlich said. Crime-scene specialists with the Washington State Patrol determined that material found on the axe blade was not blood, court papers show.
Police also have seized the man's computer browsing history, documents show. He reportedly had been looking for plane tickets out of the country for himself and his children.
The children were taken into state protective custody the day Susann Smith's body was found.
After that, police say the man began searching for solo tickets, according to his browsing history. He also reportedly was researching extradition laws for South American countries.
Rikki King: 425-339-3449; firstname.lastname@example.org
More Local News Headlines
3-D technology finds some hidden cancers but can cost more 1:52 p.m. Public Disclosure Commission calls Eyman's violations serious After audit, Lynnwood is fixing its financial problems Corey McCrea, 33: Snohomish skateboarder had found his gift Hit and run in south Everett leaves woman in critical condition 12:52 p.m. Students impressed by career opportunities at Manufacturing Day Complaints say that commerce officials helped PUD score a grant Activists pitch plan to divide Everett into districts
Our new comment system is not supported in IE 7. Please upgrade your browser here.