An upstate New York resident sued US Immigration and Customs Enforcement (ICE) for sending federal officers to his house with a warning over an email he sent to the agency’s one-time head.

David Streever, who is a US citizen, was on a trip to Finland when two officers showed up to his Rochester home in June and presented his wife with a warning notice informing him that the email he sent months earlier was considered a threat, his attorneys said. Streever sent the email in January to Todd Lyons, then the acting director of ICE, after an immigration officer fatally shot Minneapolis resident Renee Good in a confrontation caught on video during an anti-ICE demonstration.

In the email, Streever called Lyons “a monstrous human being” who “will never know peace”. He said the agency violated his rights under the US constitution’s first amendment – which include free speech – in a lawsuit filed on Monday in Washington DC.