AUGUSTA — A state ethics panel voted unanimously on Wednesday to investigate a top Republican state senator’s fundraising activities and fine an out-of-state progressive group targeting Maine Senate President Mike Thibodeau for an incomplete registration.

The investigation from the Maine Ethics Commission was welcomed by Assistant Senate Majority Leader Andre Cushing of Newport, whose sister, Laura Cushing McIntyre of Hermon, followed a civil lawsuit against him that alleges misuse of more than $1 million in family business funds with an an ethics complaint alleging some of the money was used for political purposes.

Separately, a $250 fine went to a Maine political action committee set up by Progressive Kick, a national super-PAC that has pledged $50,000 to help Democrat Jonathan Fulford of Monroe defeat Thibodeau, a Republican from Winterport.

The commission rejected an investigation of the group last week, but fined the PAC for a delay in disclosing that it was also working to support Questions 2 and 4 — a new 3 percent tax on income over $200,000 to fund education and raising Maine’s minimum wage to $12 by 2020, respectively — on the November ballot. The group called it an “inadvertent oversight.”

Maine Republican Party attorney Josh Tardy said Cushing “is looking forward to fully cooperating” with the investigation and and that Progressive Kick was trying to “operate in darkness” until the party filed an ethics complaint.

Cushing and Sen. Ronald Collins, R-Wells, will also be subjects of a Thursday hearing from the Maine Senate’s five-member ethics committee after Democrats on Monday flagged discrepancies with legislative travel reimbursements initially covered by political committees.

Earlier this month, the Bangor Daily News reported that Cushing charged more than $3,100 in travel from 2014 and 2015 to his political action committee that was reimbursed to him personally with taxpayer money. Similarly, records show that Collins’ campaign pre-paid $2,400 in Augusta hotel costs in 2014 that was reimbursed by taxpayers.

Both welcomed the Senate committee’s hearing in statements on Wednesday, with Collins saying, “I don’t believe I have done anything wrong, but if I have, I want to address it immediately” and Cushing saying “I do not feel I have violated any state or legislative rules.”