John Eric Armstrong (born November 23, 1973) is an American serial killer who was convicted of killing five female sex workers in Detroit, Michigan, but is believed to have murdered at least six more women between 1992 and 1999.

He claims to have killed in Seattle, Washington; Hawaii; Hong Kong, China; North Carolina; Virginia; Thailand; and Singapore.

In March 2001, Armstrong was found guilty of first-degree murder in the death of Wendy Jordan and sentenced to life imprisonment.

On June 18, 2001, he was additionally convicted of killing Kelly Jean Hood, Robbin Brown, Rose Marie Felt, and Monica Johnson.

[1] He would later explain that the reason he had left Brown, Felt, and Hood in sexually provocative positions after he killed them was "so [he] could always go back and have sex... [he] knew that they would always be there.