Terry Peder Rasmussen was born on December 23, 1943, in Denver, Colorado. He spent his childhood in Arizona and attended North High School in Phoenix, but he dropped out during his sophomore year in 1960. In 1961, Rasmussen joined the United States Navy, where he trained as an electrician and served until his discharge in 1967.

In 1968, Rasmussen got married and lived with his wife and their four children in Phoenix and Redwood City, California. His family later recounted that he was physically abusive, including burning one of his sons with cigarette butts. After being arrested for aggravated assault in 1975, his wife left him, taking the children. The last time the family saw Rasmussen was around December 1975 or 1976, when he visited with an unidentified woman. Their divorce was finalized in 1978.

Rasmussen moved around frequently, living in states such as Arizona, Colorado, California, Idaho, Virginia, Texas, Ohio, Oregon, and Hawaii, before eventually settling in New Hampshire in the late 1970s. He was known to travel with women and children and often worked as an electrician for oil and gas companies. While living in Manchester, New Hampshire, he used the alias "Bob Evans" and worked at the Waumbec Mill. 

In 1980, he was arrested three times for writing a bad check, theft, and diverting electric current. During his time in New Hampshire, a woman named "Elizabeth Evans" was listed as his wife, who is believed to be Marlyse Elizabeth Honeychurch, the adult Bear Brook victim, although this has never been confirmed.

In 1978, Rasmussen began dating Honeychurch, who had two daughters from previous marriages. Honeychurch was last seen on Thanksgiving Day in La Puente, California, after a dispute with her family. She left with Rasmussen and her daughters, Marie Elizabeth Vaughn, 6, and Sarah Lynn McWaters, 1. They were never seen by their family again.

On November 10, 1985, the bodies of Honeychurch and Vaughn were discovered in a barrel in Bear Brook State Park, Allenstown, New Hampshire. Both had died from blunt force trauma to the head. On May 9, 2000, a second barrel was found nearby, containing the bodies of McWaters and an unidentified child aged 2-4 years old. Investigators concluded all four were killed around the same time. The identities of Honeychurch and her daughters were confirmed through DNA profiling in 2019. The third child's identity remains unknown, but she was confirmed to be Rasmussen's biological daughter. Rasmussen died before being linked to these crimes and was never charged.

Rasmussen, using the name Bob Evans, dated Denise Beaudin, who disappeared in 1981 with her six-month-old daughter after Thanksgiving in Manchester. Authorities suspect Rasmussen killed Beaudin in California, though her body has never been found. Throughout the early 1980s, Rasmussen, posing as Lisa's father, was arrested multiple times under various aliases. He abandoned Lisa in 1986 and was eventually sentenced to prison for child abandonment in 1989. He became a fugitive shortly after being paroled in 1990.

Rasmussen reappeared in 1999 as Larry Vanner and married Eunsoon Jun in 2001. Jun disappeared in June 2002, and her body was later found buried in their home. Rasmussen was arrested and pleaded guilty to her murder in 2003, receiving a sentence of 15 years to life. His guilty plea likely stemmed from overhearing plans to conduct a paternity test on Lisa, leading to further investigation into his past. DNA tests revealed that Rasmussen was not Lisa's biological father, and he was linked to several aliases and crimes.

Rasmussen died in 2010 while in prison. In 2013, detective Peter Headley and genetic genealogist Barbara Rae-Venter identified Lisa's mother, linking Rasmussen to the Bear Brook murders. By 2017, authorities confirmed Rasmussen's identity through DNA testing. The techniques used to identify him have since been applied to other high-profile cases, including the capture of Joseph James DeAngelo. The identities of Honeychurch and her daughters were confirmed in 2019. However, the third child's mother remains unknown, and authorities believe she was also killed by Rasmussen.

Rasmussen lived near two other missing persons, Laureen Rahn and Denise Daneault, who disappeared in 1980. While there is no evidence directly linking him to these cases, his known crimes have renewed interest in these disappearances. Elizabeth Lamotte, who disappeared in 1984, was initially suspected to be connected to Rasmussen but was later identified as a victim of the Redhead murders. Investigators continue to explore Rasmussen's potential involvement in other unsolved cases, including the 1995 murder of Amanda Schumann Deza, whose body was found in a refrigerator in Holt, California.