He appeared as Cornell University professor Frank Holt who contacted the German spy network which undertook to sabotage US aid to the war in Europe against Germany.

His activities, and those of other Germans, were played up by the press as "Hun barbarity"; anti-German sentiment rose in the years as America eventually entered the war with Germany.

Muenter's baptismal record at St. Marien Church [de] list his parents as Ernst Heinrich Victor Münter (1832-1892) from Nindorf and Charlotte Lisette Julietta "Julia" Clacius (1833-1916) from Bremke.

He vowed that he would "annihilate" Chicago and Cambridge in one blow if he could for accusing him of poisoning his wife, and claimed that he actually feared the punishment inflicted on Christian Scientists who refused medical treatment.

[11] [12] He was a committed German nationalist and opposed the US policy of selling arms to Great Britain and France, Germany's enemies in World War I.

[13] Muenter went underground and assumed the name "Frank Holt", working at a gold mining company in El Oro, Mexico.

He became involved with the German spy group Abteilung IIIb, which planted time bombs on vessels carrying arms for the Allies from US ports.

[16] Muenter clearly had connections to the German network and taunted authorities with veiled statements about Abteilung IIIB's ship sabotage efforts.

[17] Muenter began a campaign against the United States and finance capital on July 2, 1915, by hiding a package containing three sticks of dynamite with a timing mechanism set for nearly midnight under a telephone switchboard in the Senate reception room in the United States Capitol, Washington, D.C. His original target had been the Senate chamber, which he found locked.

Here, he placed a pencil bomb timed explosive aboard the SS Minnehaha, a ship loaded with munitions bound for Britain.

[20] Under the alias of Frank Holt, Muenter took a train and a cab to the East Island, Glen Cove, New York, estate of J. P. Morgan Jr. on July 3, 1915.

Inspector of Combustibles Owen Egan declared it "the greatest equipment for bomb making ever brought to New York" with 134 sticks of dynamite, blasting caps, coils of fuse, batteries, nitric acid, windproof matches, mercury fulminate, smokeless explosive powder.

[28] [29] In Howard Blum's In Dark Invasion he writes that New York's counterterrorism police at first believed that he was killed by an assassin sent to silence him with two bullets in the head.

[1] But the version they decided on was that Muenter ran out of a briefly opened door and jumped head-first onto the concrete floor of the jail corridor (this source says he fell to his death from 20 feet (6.1 m)).

[11][12] The sound of his head hitting the concrete was so loud that it was initially thought he had smuggled a dynamite cap into the prison and set it off with his teeth.