Collins was a graduate student at the University of Virginia (UVA) in Charlottesville, Virginia in 1986. His landlady saw him as he left his apartment on March 21, 1986. She gave him some grapefruit and oranges, and he rode away on his bicycle.

Collins's classmates notified authorities of his disappearance two weeks later. On his desk in his office in Jordan Hall on the UVA campus were his eyeglasses, keys, and day pack. Inside the pack was Collins's wallet, empty, with his identification scattered loose at the bottom. The landlady's fruit was rotting on a shelf nearby. Collins's loved ones say it is uncharacteristic of him to leave without warning or to leave his wallet unattended. After his disappearance, some meat was found defrosting on his kitchen counter. He left behind $528 in his bank account as well. Bank records showed that Collins withdrew $40 from an automatic teller machine (ATM) the day after his landlady last saw him. The money has never been found.

Authorities initially believed Collins left of his own accord, pointing to a $200 advance he'd taken on his credit card on March 19, but it was established that he spent the money on textbooks. His stepfather, a retired police detective, thinks he walked in on a burglary at his office on campus and was murdered as a result. Another graduate student who shared Collins's office had three personal checks stolen from the office around the time Collins vanished; the crime has not been solved. Collins's stepfather believes a local man with a history of forgery and petty theft stole the checks and murdered Collins. The suspect fled the Charlottesville area shortly after Collins vanished. He was arrested in Maryland two days later. The police investigating Collins's disappearance do not believe the individual was involved, however.

Collins is a native of San Jose, California and grew up in a violent household with an abusive, alcoholic father. His father was murdered in California in 1979 and the crime was never solved. Collins was an Eagle Scout and has a black belt in judo. He worked through college and obtained a psychology degree from the University of California at Davis, graduating near the top of his class. Ten weeks before his disappearance, he was enrolled at Ph.D. program in physiology at UVA and dreamed of becoming a cardiovascular physiologist. He has two siblings, but his sister died of cancer in 2003; only his brother survives. His mother and stepfather are also still alive.

Collins's family sharply criticized the UVA Police Department for mishandling the investigation into his disappearance. Decades after the fact, an FBI agent who examined the case said the UVA police's investigation "failed to meet even minimal standards." The UVA police were extremely reluctant to admit the possibility of a crime in Collins's case, insisting for months and against contrary evidence that he had simply walked away from his life. Little evidence is available in Collins's disappearance and case remains unsolved.