A judge hearing the case of Guido Amsel has ruled there are enough similarities and linkages connected to four bombing events that she can conclude they are not coincidental and are the responsibility of the same person.

Lord's decision came one day after prosecutors argued a similar fact motion that would allow Lord to use the evidence of one bombing incident to assess another.

Without a similar-fact ruling, when dealing with multi-count indictments, evidence in relation to individual counts is considered presumptively inadmissible when evaluating the evidence of another.

"I am satisfied that the standard of 'striking similarity' has been met and that the similarities are sufficient to establish that the alleged similar acts were committed by the same person," Lord said. Three bombs were delivered to Amsel's ex-wife Iris and two lawyers in July 2015.

Judge Tracey Lord

Judge Tracey Lord, sketched in November 2017 during the trial of accused letter bomber Guido Amsel. (CBC)

All three bombs were delivered by Canada Post, addressed to people involved in litigation with Amsel, Lord said. All three bombs used the same easy to obtain, highly explosive material, and all included messages to the recipients or targets.

A bomb that exploded outside Iris Amsel's RM of St. Clements home in December 2013 was linked to one of the same targets and was delivered just after the conclusion of a contentious court proceeding involving the accused and his ex-wife.

A piece of string seized at the 2013 bomb scene was found to have Guido Amsel's DNA on it, as did a plastic pouch found at a 2015 explosion at a River Avenue law office that seriously injured lawyer Maria Mitousis.

"I am satisfied by the evidence on a balance of probabilities of the objective improbability of these four incidences being coincidental," Lord said.

Following Lord's ruling, the Crown officially closed its case.

The trial will resume Wednesday, at which time the defence will either call evidence or close its case.