The Internal Revenue Service placed a $3.27 million lien for unpaid payroll taxes on Professional Educational Services Group LLC on Oct. 8 — two weeks before the education staffing firm abruptly ceased operations last week, Crain’s Detroit Business reported. PESG owes the IRS $3.15 million in unpaid income, Social Security and Medicare taxes that were withheld in 2017 from the paychecks of nearly 2,000 substitute teachers and an additional $119,000 in unemployment insurance taxes.