Criminal Charges in 1997 of attempted murder and aggravated assault
against Robert Pickton were dropped, possibly because the victim would
not or could not testfy.

http://seattlepi.nwsource.com/local/57736_vancouver09.shtml

"Friends and relatives of the missing women say they became aware of
Robert Pickton after his name surfaced in 1997, when a prostitute and
drug addict accused him of trying to stab her to death during an
encounter at the farm in 1997. Pickton was charged with attempted
murder, aggravated assault and unlawful confinement, but charges were
later dropped. The woman, who had run screaming from the farm in
handcuffs, reportedly refused to testify. Her whereabouts is unknown."

Now, the RCMP and the Vancouver Police Department created a joint task
force in April, 2001.

http://www.rcmp-bcmedia.ca/pressrelease.jsp?vRelease=567

"The Vancouver Police Department (VPD) and the RCMP joined forces in
April 2001 to review all the reports of women missing from the
Vancouver downtown eastside to look for any information or common link
that may assist in discovering who may be responsible for their
disappearances." 

In February 2002, within a year of the  task force formation, police
were searching the property of the erstwhile pig farmer, Robert
Pickton.


http://www.rcmp-bcmedia.ca/pressrelease.jsp?vRelease=784

It must be said that the farm is not within the city limits (ie. jurisdiction)
of the municipal force.

Q1) Why did "the police", be they VPD, RCMP, or Port Coquitlam
municipal police (if there is such a thing)  not link the Pickton
brothers sooner?

Q2) Has a body of case law arisen since Canada's 1982 Charter of Rights that
has had a cumulative effect of impeding the police?
-there are examples of terror-related suspects that various police forces 
claim are un-chargeable.

 
Please be sure that the question is not an attempt to lay blame at an
individual policeman's feet, but since murders continued between 1997
and 2002 it is a fair question.