06/17/2015 09:03 EDT | Updated 06/17/2016 05:59 EDT

Mike Duffy trial: Accountant testifies about suspended senator's finances

Forensic accountant Mark Grenon, who has reviewed thousands of Mike Duffy's financial transactions, will continue testifying during a voir dire — a sort of trial within a trial to determine admissibility of evidence.

Duffy has pleaded not guilty to 31 charges of fraud, breach of trust and bribery related to expenses he claimed as a senator and later repaid with money from the prime minister's then chief of staff, Nigel Wright.

​Duffy's judge-only trial, which began April 7 in the Ontario Court of Justice, is in its 35th day. Following the voir dire, Judge Charles Vaillancourt will determine how much, if any, of the testimony will be admissible.

Duffy's lawyer Donald Bayne has argued against the admissibility of much of Grenon's testimony, questioning its relevance and the objectivity of Grenon.

On Tuesday, Grenon testified that according to his review, Duffy was withdrawing more money from his bank account than he was depositing and was forced to fund the difference with his line of credit.

​Grenon said that he also discovered $159,477 of unknown deposits in Duffy's bank account. He said $50,000 of that total could be related to an inheritance, but that would still leave more than $109,000 unaccounted for. Grenon said if there is more information or documents available, he would be open to reconciling the remaining amount.

As well, court heard that Duffy expensed nearly $154,000 in travel expenses that the Crown alleges the suspended senator was not eligible to claim.

Grenon has looked into the following areas of Duffy's financial records:​

- Claims analysis.

- Duffy's financial practices (bank records, credit, mortgages).

- Contracts with Duffy associate Gerald Donohue and the cheques from Donohue's family's business.

- Tracing the $90,000 payment from Wright.