Senator Mike Duffy and his wife recently took out a $550,000 mortgage on the Ottawa-area home that jurors may hear about at his upcoming trial.

Sen. Duffy and his wife Heather Duffy purchased the home in Kanata, Ont., for $292,783 in 2003, and took out a $550,000 mortgage against the property from Royal Bank in November 2014, provincial land registry documents show.

Sen. Duffy will face 31 charges, including breach of trust, fraud and bribery, during his trial beginning on April 7.

The charges, announced by the RCMP last July, relate to the living expenses that senators may only claim if their primary residence is more than 100 kilometres from Ottawa.

Sen. Duffy, who represents Cavendish in Prince Edward Island, has maintained that his primary residence is on the island, and that his other travel expenses were filed in error.

Both Sen. Duffy’s residence on P.E.I. and the Kanata home are listed on the land-registry document connected to his recent mortgage.

Among the charges Sen. Duffy faces in relation to his residency expense claims are one count each of fraud over $5,000 and breach of trust.

The charges have cast a shadow on the Conservative party that appointed Sen. Duffy, and later kicked him out of caucus.

Sen. Duffy, along with fellow Conservative appointees Sen. Pamela Wallin and Sen. Patrick Brazeau, were suspended without pay in November, 2013 after all three were accused of inappropriately claiming living expenses related to residences in their home provinces.

None of the allegations against them have been proven in court.

The base salary of a senator in 2013 was $135,200, according to the Library of Parliament.