Can a debt collector send a letter to my employer?

Hello. Yesterday my manager received a letter in our store mailbox from Cohen & Slamowitz. It was to be forwarded to our payroll department. The letter had all of my personal information including my SSN. It detailed my debt amount and listed a judgement against me from 2009. I haven't received an income execution order from the sheriff or heard about an impending garnishment. Can they send this information to my employer? I thought I was supposed to be notified first by the sheriff and given the option to voluntarily set up payments with the county clerk.