What is "slumach"

Slumach who died on the gallows in New Westminster, British Columbia, Canada, in 1891 was an elderly Katzie First Nations man. Baptized moments before his death he was given the first name "Peter", a name never used in his lifetime. His unmarked grave is in St. Peter's Cemetery in Sapperton. He is remembered today because of his alleged knowledge of the location of the Pitt Lake gold deposit that is often referred to as "Slumach's Gold."