03/12/2013 02:26 EDT | Updated 05/12/2013 05:12 EDT

Winnipeg police charge alleged serial killer Shawn Lamb with 2011 sex attack

WINNIPEG - Police have charged an accused serial killer in Manitoba with a sex attack that is alleged to have happened two years ago.

Shawn Lamb faces a new charge of sexual assault with a weapon.

Police allege that at some time in November or December 2011, he picked up a woman in central Winnipeg and drove her to a secluded area and attacked her. She fled to a nearby business and police were called.

Lamb, 53, remains in custody and is set to appear in court again Thursday.

The drifter, originally from Sarnia, Ont., was charged last June with second-degree murder in the deaths of three missing aboriginal women.

The bodies of Lorna Blacksmith, 18, and Carolyn Sinclair, 25, had been discovered wrapped in plastic near city garbage bins earlier in the year.

The remains of Tanya Nepinak, 31, have never been found. She was last seen in September 2011 and police believe her body was put in a garbage bin that was taken to a landfill.

With no information on where a garbage truck emptied that load, police called on an aboriginal elder to select a small section of the sprawling dump for officers to search.

After a week of combing through garbage, the search was called off.

No trial date has been set on the murder charges.

Following Lamb's arrest last year, Winnipeg police set up a national tipline and contacted other police agencies across the country to see if he could be linked to other missing women.

The case also prompted new calls from aboriginal leaders for a national inquiry on missing and murdered aboriginal women. The federal government rejected the idea.