In his second day as a witness at the perjury trial of former RCMP corporal Monty Robinson, Dietrich testified that all four Mounties met at the home of his ex-spouse Janice Norgard sometime in May 2009.
Dietrich's testimony directly contradicts that of Norgard, who went to the Crown last year with a story that the meeting happened in January or February 2009, before any of the officers appeared at the Braidwood Inquiry.
If true, the officers could be found guilty of perjury, because at the inquiry each denied having met before giving their testimony.
However, the special prosecutor has been forced to acknowledge that Norgard's version of events is circumstantial, and there is no corroboration for her claim.
In the course of Robinson's trial, significant doubt about the allegation was raised after phone, internet and banking records supported Dietrich's version of events.
Flight details, RCMP documents and testimony from the lawyer for one of the officers also suggest the Mounties were never in the same province, let alone the same city, at the time Norgard alleges the meeting occurred.
Mountie meeting raises questions
On Wednesday, Dietrich testified that he helped his cousin, Const. Bill Bentley, get together with his former fellow officers in May 2009.
"Bill called me and asked me if there was a place that the four of them could meet," Dietrich testified.
"He asked me specifically if they could meet [at Norgard's house] and if Janice would mind. I told them I didn't think Janice would mind."
Special prosecutor Scott Fenton cross-examined Dietrich on a recorded interview he gave to police when they first appeared at his doorstep last year to investigate Norgard's claim.
Fenton got Dietrich to agree that the death of Dziekanski and the subsequent inquiry were for his close cousin Bill Bentley "a traumatic event in his life" and "the biggest bad thing that ever happened to him."
"I'm sure it was for all four of them," Dietrich replied.
In the police interview, as the investigators peppered Dietrich with leading questions, Dietrich told them, "I have no recollection of any meeting four years ago."
Later on, he told them, "I think he met with them a couple of times, I don't know."
Fenton suggested Dietrich was worried he would implicate his cousin in collusion.
"You were concerned about giving an answer that would support that the four officers met before they testified at Braidwood," Fenton said.
"I was concerned I'd give an incorrect answer," Dietrich replied.
Fenton pointed out that Dietrich never revealed to police that Bentley had stayed with him numerous times.
"You don't say anything about Bill Bentley staying with you during the Braidwood Inquiry. It was the biggest event, you've agreed with me, in your cousin's life. It was not something that you would forget," Fenton said.
"Your cousin ... your close friend coming to testify at this high-profile inquiry, but you don't make any mention here."
"I told you I was really nervous," Dietrich answered. "I'm sorry it was a lousy statement."
Fenton suggested Dietrich was trying to mislead the police.
"Sir, I'm going to put it to you … you did remember this meeting — this meeting they're interested in and asked you about several times".
"You wouldn't tell them anything, because you'd be concerned it would implicate your cousin and the other officers in collusion."
Dietrich rejected Fenton's assertion and said he wanted to be careful about misspeaking while two police officers recorded the conversation.
"If I said anything and it was wrong, it would be used against him later."
Robinson's trial is expected to resume next week.