12/08/2014 12:00 EST | Updated 02/07/2015 05:59 EST

Garry Taylor Handlen to make court appearance in Abbotsford

The man charged last week with the first-degree murder of two B.C. girls in the 1970s is expected to make his first court appearance this morning in Abbotsford.

Last week, the RCMP announced that Garry Taylor Handlen, 67, had been arrested and charged with the murder of 11-year old Kathyrn-Mary Herbert and 12-year-old Monica Jack.

Herbert disappeared in September 1975 close to her home in Abbotsford, B.C., while returning from a friend's house. Two months later, her body was found hidden under a rotting outhouse on the nearby Matsqui First Nation.

Jack disappeared three years later in 1978 while riding her bike. Her body was not found until the mid-1990s north of Merritt.

Last week RCMP said Handlen was suspected in the killings shortly after they happened, but police didn't have enough evidence to charge him until recently.

Investigators wouldn't specify what the new evidence is, but said advances in forensic science are a factor.

Police also released a photograph of Handlen, taken around the time of the killings, asking anyone who recognizes him to call if they have any memories of him from that time.