70's & early 80's.
Note that I know the area well have travelled, worked, & fished there extensively in addition to living an hour's drive away-will be working there again in 3 weeks time.
I grew up there in the 70's and 80's there was plenty of drug trafficking going on then. Four people I went to school with were killed in separate incidents due to the drug trade. One was killed in a drive by shooting in the 80's, another was killed by the cop he attacked, the other two were murdered by the people they associated with. And those were people I knew. There were plenty of other incidents. In fact Chilliwack and Abbotsford had a reputation for high crime rates back then. That and most churches per capita.
I will say the Fraser Valley population has exploded and grown. But Chilliwack, Abbotsford and the outlying communities had it's fair share of rough customers even then.