VA hospital staff members speculated that Gilbert may have been responsible for 350 or more deaths and more than 300 medical emergencies. The prosecutor in her case, Assistant U.S. Attorney William M. Welch II, asserted that Gilbert used these emergency situations to gain the attention of then-boyfriend Perrault, a VA police officer—hospital rules required that hospital police be present at any medical emergency. Perrault testified against her, saying that she confessed at least one murder to him by phone while she was hospitalized in a psychiatric ward. Defense attorney David P. Hoose claimed reasonable doubt based on a lack of direct evidence.

In July 2003, Gilbert dropped her federal appeal for a new trial after a then-recent US Supreme Court ruling that would have allowed prosecutors to pursue the death penalty upon retrial.

On March 14, 2001, a federal jury convicted Gilbert on three counts of first-degree murder, one count of second-degree murder and two counts of attempted murder. Though Massachusetts does not have capital punishment, her crimes were committed on federal property and thus subject to the death penalty. Prosecutors, in an attempt to secure a penalty of death, sought to admit evidence of aggravating factors during the penalty phase, including Gilbert’s 1998 conviction for the bomb threat; the defense introduced evidence of mitigating factors, including the well-being of Gilbert’s two children.

On March 26, 2001, the jury recommended a sentence of life imprisonment. On March 27, the judge formally sentenced Gilbert to four consecutive life terms without the possibility of parole, plus 20 years.

Gilbert has two sons with Glenn Gilbert. The couple divorced in 1998.

Gilbert left the hospital in 1996 amid a hospital investigation into the many suspicious patient deaths that occurred during her shifts. That fall, Gilbert checked herself into psychiatric hospitals seven times, staying between one and 10 days each time. In January 1998, Gilbert stood trial for calling in a bomb threat to the Northampton VAMC to retaliate against coworkers and former boyfriend James Perrault (who also worked at the hospital) for their participation in the investigation. In April 1998, Gilbert was convicted of that crime.

Prosecutors said that Gilbert abandoned a patient undergoing cardiac arrest on Nov. 9, 1995, and then asked another nurse to accompany her on a check of patients. Prosecutors said she waited until her colleague independently spotted the patient’s difficulty before raising an alarm. Gilbert forced an untrained colleague to use cardiac defibrillation paddles on a patient during a medical emergency on Nov. 17, 1995, by refusing to use the equipment herself. Prosecutors said Gilbert threatened the life of at least one person verbally and physically in July 1996. While working as a home health aide before becoming a registered nurse and about eight years before her VAMC crimes, Gilbert purposely scalded a mentally handicapped child with hot bath water.

In 1989, she joined the staff of the Veterans Affairs Medical Center in Northampton. She was featured in the magazine VA Practitioner in April 1990. Although other nurses noticed a high number of deaths on Gilbert’s watch, they passed it off and jokingly called her the “Angel of Death.” In 1996, however, three nurses reported their concern about an increase in cardiac arrest deaths and a decrease in the supply of epinephrine, and an investigation ensued. Gilbert telephoned in a bomb threat to attempt to derail the investigation.

According to court records, Gilbert had made violent threats against others since she was a teenager. At the trial, prosecutors said Gilbert used a large kitchen knife in an assault in Greenfield, Massachusetts in January or February 1988. Prosecutors said she tried twice to murder a person by poison in November 1995. Prosecutors said that Gilbert tried to poison a patient at the VA hospital on Jan. 28, 1996, and that she caused a medical emergency by removing a patient’s breathing tube at the VA hospital on Jan. 30, 1994.

She graduated from Groton-Dunstable Regional High School in Groton, Massachusetts. In 1986, she enrolled at Bridgewater State College in Bridgewater, Massachusetts. After a fake suicide attempt, Gilbert was ordered psychiatric treatment by Bridgewater State College officials. Because of this, in 1987, she transferred to Mount Wachusett Community College in Gardner, Massachusetts and then to Greenfield Community College in Greenfield, Massachusetts. She graduated from the latter with a nursing diploma, becoming a registered nurse in 1988. Later that year, she married Glenn Gilbert.

Kristen Heather Gilbert (born Kristen Heather Strickland, November 13, 1967) is a former nurse and an American serial killer who was convicted of four murders and two attempted murders of patients admitted to the Veterans Affairs Medical Center (VAMC) in Northampton, Massachusetts. She induced cardiac arrest in patients by injecting their intravenous therapy bags with massive doses of epinephrine, an untraceable heart stimulant. She would then respond to the coded emergency, often resuscitating the patients herself.

Gilbert was born on November 13, 1967, in Fall River, Massachusetts, the elder of Richard and Claudia Strickland’s two daughters. Richard was an electronics executive, while Claudia was a homemaker and part-time teacher.