The trial of accused letter bomber Guido Amsel was told about a 20-centimetre deep crater and an extensive debris field after a blast at the home of his ex-wife.

RCMP Sgt. Yvette Alarie testified that she was called to the home in the Rural Municipality of St. Clements on Dec. 14, 2013, a day after the explosion.

Alarie said she did a walk around of the property and took pictures of what she saw, including the crater near the garage, black staining on the garage wall, a broken window and crumpled building material.

"The idea is to record the crime scene as found," Alarie said. 

The debris field extended 70 metres to the next property, Alarie told court.

She swabbed the crater and stain for DNA, and turned the material over to another officer the following day.

Defence lawyer Saheel Zamen suggested that evidence was unreliable since Alarie had no way of knowing who all had access to the scene following the explosion. For instance, an insurance adjuster had visited the property prior to her arrival, Zamen said.

"What they touched or may have moved, you can't tell us," Zamen said.

"No, I cannot," Alarie agreed.

Amsel, 51, is charged with five counts of attempted murder and several explosives-related offences. He was arrested in July 2015 after packages containing bombs were mailed to his ex-wife and two law firms.

Lawyer Maria Mitousis lost her right hand and suffered other injuries when one of the bombs detonated. The other two bombs were safely detonated by police.

Shortly afterwards, Amsel was also charged in connection with the 2013 blast.

Winnipeg Police Service Insp. Brian Miln was assigned to the bomb unit when he received word of the River Avenue blast that injured Mitousis. 

Miln told court he arrived at the scene at 11:20 a.m., an hour after the blast, and charted a course of action with other members of the bomb unit.

"The other concern was making sure there was a safe perimeter around us and no secondary devices that would pose a danger to emergency responders," Miln said. 

Miln assigned two members to attend inside the law office and search for missing body parts that could be rushed to hospital for possible reattachment. None were found, he said.

Miln said officers followed a strict post-blast scene protocol to ensure evidence was not contaminated. Officers wore protective gear at all times and two pairs of latex gloves.  

"With explosives, there is going to be trace evidence present," Miln said. "We wanted to ensure absolute care was taken from the beginning" to avoid cross-contamination.

Robot detonated suspected second bomb

Miln said he took a swab of a plastic cell phone pouch and it tested positive for a homemade explosive called TATP.

"It's a common explosive that can be made in somebody's home," Miln said. "I notified the identification technician at the scene that this is going to be a significant piece of evidence."

The next day, police received a report of a suspicious package at a Washington Avenue auto-body shop.

"The information was there were similarities to the package delivered to River Avenue," Miln said. "We were treating this as another explosive device based on that."

Police secured the scene and used a bomb robot and water cannon to detonate the bomb. A police video played in court showed the robot searching for the package and detonating it. 

Miln said the large amount of airborne debris visible in the video and damage to the roof and building "confirmed to me that a detonation had occurred."