OTTAWA, Ontario - A search turned up additional human remains near a property linked to a self-employed Toronto landscaper who has been charged with the killings of eight people, Toronto police said Thursday (July 5).

"It was a bit of a surprise," Detective Sgt. Hank Idsinga told reporters.

Earlier this year the police discovered the dismembered remains of seven men buried in planters at a home whose gardens and lawns had been maintained by the landscaper, Bruce McArthur. McArthur was charged then with eight counts of first-degree murder, although the remains of an eighth victim have yet to be discovered.

McArthur's victims for the most part were from Toronto's gay community; six of the men were of South Asian or Middle Eastern descent.

The serial killings have further strained relations between Toronto's police force and gay activists, who accuse the force of failing to seriously investigate missing persons cases involving gay men that stretch back nearly a decade. In late June, the city agreed to hold an independent review of how bias affects police investigations of missing persons.

The latest police discovery was made in a ravine behind a house owned by former clients of McArthur who also let him store equipment and supplies in their garage. It was the only one of about 100 sites linked to McArthur that was flagged in May by dogs trained to find human corpses.

"We are prioritising areas that give us the strongest indications with canine units," Idsinga, the lead investigator in the case, said Thursday. "The excavation continues, and we anticipate being here for, at least, until next week." Police were unable to intensively search the area during the winter because the ground was frozen. They then had to make arrangements with government agencies to minimize environmental disruption of their excavations to the ravine.

Forensic pathologists are trying to identify the remains, which were found late Wednesday afternoon and placed in a large black bag before being moved into a van belonging to the Ontario coroner's office. Police did not speculate about whether the remains were those of an additional victim or victims.

It appeared that the police search was focused on a compost pile.

The allegations against McArthur have shocked many in Canada, and the discovery of the bodies in otherwise festive garden planters have given the case a particularly macabre edge, making it one of the most notorious Canadian serial killings of this century.

In 2007, Robert William Pickton, a pig farmer in British Columbia, was convicted of killing six women although DNA evidence suggested that he murdered as many as 49 women, most of them prostitutes from Vancouver. A subsequent investigation faulted police bias for allowing Pickton's rampage to continue.

In 2010, the former commander of a major Canadian air force base pleaded guilty to two murders and 84 other sexually related crimes that he meticulously documented with photographs and video. And just over a year ago, a nurse pleaded guilty to murdering eight nursing home patients under her care. An inquiry into that case is underway.

Since McArthur's arrest, it has emerged that he was twice questioned and released by police. In 2003, he pleaded guilty to hitting a prostitute with a metal pipe in that man's apartment. McArthur's conditional sentence included an order banning him from a downtown Toronto neighborhood with several gay bars that was frequented by several men he is now accused of having killed.

One of two psychological reports from the 2003 case, which a court released this past week, found that there was a "minimal" risk that he would be involved in additional violence.

McArthur, 66, was once married and has two children. The reports said that he separated from his wife in 1997 after accepting his sexual orientation. But, the psychologists concluded, he had had difficulty dealing with being gay while growing up on a farm in rural Ontario.

"He felt he could never please his father," one report said. "Looking back, the subject questions whether this was due to his father sensing his homosexuality or lack of masculinity." Police have said little about McArthur's motives. After he left his wife, McArthur became relatively well known and generally liked in the neighborhood from which the victims vanished. Most were middle-aged and many were immigrants, officials said.