At least two occurrences mentioned in the plea deal raise concerns about payments influencing union business.
The first, feds say, took place in December 2013. Iacobelli, according to the plea deal, sent an email to another "FCA executive" confirming that then-UAW Vice President General Holiefield, now deceased, had been "scripted" ahead of a meeting with other members of the union's International Executive Board.
At the time, the board was considering the terms of a multibillion-dollar offer to purchase equity interest held by the UAW Retiree Medical Benefits Trust, also known as a Voluntary Employees' Beneficiary Association, in Chrysler Group, now known as FCA US.
The transaction was completed a month later.
Federal investigators say the second occurrence happened in February and March of 2015. FCA, according to the plea, offered to make confidential retirement offers to "senior UAW officials."
Targeted buyouts are not uncommon, but they are typically based on job classification, department or years of seniority and not exclusively offered to hand-picked senior leaders.
UAW officials, including Williams, have contended that the alleged activities could not have affected negotiations because union members have the final vote on the contracts, which are bargained among dozens, if not hundreds, of individuals.
Williams, in the Friday letter, refuted claims of Holiefield influencing the VEBA meeting. Holiefield, according to Williams, "said nothing" at the VEBA meeting "that anyone who participated can recall."
Regarding the buyouts, Williams confirmed they existed, however said they were "immediately rejected" and "never paid to anyone."
A UAW spokesman last week reiterated that the union is "appalled at these charges" and has taken measures to "reduce the risk of any future recurrence of these activities." He declined to comment directly on the newest allegations, referring to previous statements from Williams.
Dziczek agrees it would have been difficult for such activities to corrupt the union's collective bargaining.
"Given that the UAW relies on pattern bargaining — where one deal serves as the blueprint for the agreement at the other two represented automakers — the numbers of individuals involved would be multiplied three times over," she said.
"It is difficult to fathom that the alleged conspiracy stretches that far and wide."
Iacobelli is one of four people charged in connection with the case. The others are Virdell King, a retired UAW associate director; Jerome Durden, a former FCA financial analyst; and Monica Morgan, Holiefield's widow. Durden and King pleaded guilty to charges and will be sentenced this year.