The union representing Boeing's engineers and technical workers has filed an unfair labor practices complaint.
The Society of Professional Engineering Employees in Aerospace claimed Boeing videotaped members engaged in solidarity marches, seized cameras from some employees and deleted photos of the marches.
A Boeing spokesman told The Daily Herald the company hasn't been served with the complaints, so it could not comment on them.
SPEEA said it filed the complaint against Boeing Friday after receiving complaints from members at multiple Boeing locations.
For the last several weeks, SPEEA members have held marches, meetings and other events at many Boeing facilities to show support for their SPEEA negotiation teams.
Marches ranged from a few dozen employees to more than 2,500 at the Everett plant, SPEEA said.
SPEEA and Boeing started meeting weekly in April to negotiate new contracts for 23,000 engineers and technical workers at facilities around Puget Sound, Portland, Utah and California.
Boeing presented new contract offers Sept. 13. Engineers and technical workers rejected the offer.
The next negotiation session is scheduled for Wednesday.