Susan Collins

The Democrats vying to replace Graham Platner as the party’s Senate nominee in Maine quickly seized on the Monday shooting of a man in Biddeford by federal immigration agents, with some aiming to tie Senator Susan Collins, the Republican incumbent, to President Trump’s immigration crackdown.

Two of the Democratic candidates, Dr. Nirav Shah and Troy Jackson, rushed to Biddeford to participate in a demonstration against Immigration and Customs Enforcement, with Mr. Jackson joining protesters outside Ms. Collins’s office in the city and vowing to “abolish ICE.”

Federal authorities had yet to provide information about the shooting as of Monday evening, but the state attorney general said that an ICE agent had killed a man during an operation in Biddeford, a coastal city south of Portland. The man who was killed, who pro-immigrant groups have said was a 26-year-old from Colombia, “attempted to flee in a vehicle in the direction of the officer and was fatally shot,” the attorney general, Aaron M. Frey, said.

On Monday afternoon, as details emerged about the shooting, Ms. Collins called for a “full and impartial investigation of what happened.”

But as Maine Democrats prepare for a convention in late July where state party delegates will choose a new Senate nominee, several potential challengers to Ms. Collins pointed to her past votes on ICE.

As the chairwoman of the Senate committee overseeing government spending, Ms. Collins this year advanced a bill that would have included money for body cameras and de-escalation training for immigration enforcement officers. But after Democrats would not vote to fund ICE and Customs and Border Protection, Ms. Collins later voted with Republicans to give both agencies $70 billion through a special congressional budget procedure that did not allow Congress to impose those guardrails on immigration agents.

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