One of the police investigators took the stand Thursday in the trial of 57-year-old Brian Malley.
Malley is charged with first-degree murder and two explosive-related counts in the November 2011 death of 23-year-old Victoria Shachtay.
The investigator says they watched Malley eat at a restaurant in February 2012, then they retrieved the napkin from the garbage.
Court has heard Malley's DNA was found on part of the packaging that was used to disguise a homemade pipe bomb as a Christmas gift.
The explosive was left on Shachtay's doorstep and she died when she opened it.
The Crown contends that Malley, who was Shachtay's financial adviser, lost more than half a million dollars Shachtay received in a settlement after a crash that left her without the use of her legs, and killed her because he had been covering the losses by paying her out of his own pocket.
The defence says evidence will show some of the woman's relatives had addiction problems and the real killer was someone who wanted to send a message to Shachtay or her family.
(CHUB, The Canadian Press)