Thor Nis Christiansen (28 December 1957 – 30 March 1981) was a Danish-American serial killer and necrophile from Solvang, California.

He committed his first three murders in late 1976 and early 1977, killing young women of similar appearance from nearby Isla Vista.

His crimes motivated large demonstrations opposed to violence against women, and in favor of better transportation for the young people residing in Isla Vista.

The family initially settled in Inglewood, California, and then moved to Solvang, where his father, Nis, ran a restaurant.

[2] Christiansen's modus operandi was to pick up hitchhikers, shoot them in the head with a .22 caliber pistol, and sexually assault them post-mortem.

[6] On January 19, 1977, Patricia Laney, 21, was found shot to death, the day after she was reported missing, in Refugio Canyon near Santa Barbara.

[9] On July 27, 1979, after interviewing more than 115 people over the previous two years, police arrested Christiansen for the murders of Patricia Laney, Jacqueline Rook, and Mary Sarris.

"[15] During the trial, a psychiatric evaluation of Christiansen revealed he suffered from an "intermittent explosive disorder," a paranoid personality, chronic drug use, and necrophilia.

[4][19] On March 30, 1981, Christiansen died after being stabbed once in the chest while walking in the exercise yard at Folsom State Prison.