Despite the Fifth Amendment's Double Jeopardy Clause prohibiting retrials after acquittals, the United States Army was able to initiate prosecution and trial proceedings against Hennis under the dual sovereignty doctrine.
In May 1985, Eastburn was undergoing training at a squadron's officer school in Montgomery, Alabama, with his wife and children remaining in Fayetteville.
[2][4] Timothy Baily Hennis (born February 24, 1958)[5] grew up in Rochester, Minnesota, and graduated from Mayo High School in 1976.
[6] Since the Eastburn family was planning to relocate to England so that Eastburn could take up a liaison job with the Royal Air Force, Katie made arrangements to rehouse the family's English Setter Dixie, posting an advertisement in the local newspaper Beeline Grab Bragg.
On May 12, a concerned neighbor named Bob Seefeldt and a police officer visited the home, where they discovered the remains of Katie, Kara, and Erin.
[4] Detectives Robert Bittle and Jack Watts of the Cumberland County Sheriff's Office were in charge of the homicide investigation.
[2] On the first night of the investigation, a janitor named Patrick Cone approached Bittle and Watts, telling them that he had witnessed a tall white man dressed in jeans, a knit cap, and a black "Members Only" jacket exiting the Eastburns' driveway carrying a garbage bag in the early morning hours of May 10.
Cone also helped the North Carolina State Bureau of Investigation produce a composite sketch of the suspect.
[2][3] Following media coverage of the Eastburn killings, Hennis visited the local police station on May 15, where he submitted to interrogation by Watts and Bittle.
In addition, Hennis also provided investigators with blood, saliva, and hair samples and finger and palm prints.
Due to his close resemblance to the composite sketch, investigators identified Hennis as the prime suspect from the onset.
Investigators determined that Katie's stolen ATM card had been used twice, on the night of May 10 and the morning of May 11, with the two transactions amounting to a total of US$300.
Investigators sought to link this to Hennis being late on his monthly rent payment and his prior convictions for writing bad checks.
Before the trial, the prosecution offered Hennis a plea bargain: two counts of second-degree murder, with a likely penalty of two consecutive life sentences.
[2] During the trial, VanStory and his team put forth the theory that Hennis had taken advantage of his wife Angela's absence to initiate a romantic relationship with the married Katie Eastburn.
In addition, the prosecution drew upon Cone and the female's eyewitness accounts and the transactions resulting from Katie's stolen ATM card.
[6] During the retrial held in April 1989, Beaver and Richardson represented Hennis while the prosecution consisted of Calvin Colyer and John Dickson, who had replaced VanStory.
In addition, Beaver and Richardson presented two new defense witnesses: a newspaper delivery woman who claimed that she saw a long-haired man driving a light-colored van on the morning of May 11 and a local teenager from the Eastburns' neighborhood named John Raupaugh who was jogging near the Eastburns' family home on the night of the murder.
[2] In May 2005, Captain Larry Trotter of the Cumberland County Sheriff's Office attended a detectives' seminar on advanced criminal-intelligence techniques, which discussed the Eastburn murders as a case study.
After conversing with the journalist Scott Whisnant, who had covered the Eastburn murder trials, Trotter learned that detectives had extracted semen from Katie's body using a vaginal swab.
[2][7] Trotter had the semen on the swab tested at the North Carolina State Bureau of Investigation's crime laboratory in Raleigh.
[4][2][7] Trotter shared the results with Edward Grannis, the Cumberland County district attorney, and Robert Bittle, who had participated in the 1985 investigation.
[2][8] On September 26, 2006, Hennis was recalled to military duty and returned to Fort Bragg the following month, quitting his job at the waste treatment plant in the process.
Colonel Patrick Parrish presided over the court martial proceedings while a jury panel of 14 military officers and non-commissioned personnel was convened.
[2] Spinner's defense team argued that the footprints, blood, and hair samples found at the crime scene did not match Hennis or the victims.
Prosecutor Jody Young questioned the defense attorneys' motives because they had argued that Hennis had consensual intercourse with the victim, Kathryn, before her murder.
Judge Colonel Parrish denied the defense's request to obtain documents from the investigation into the SBI lab.
[17] Defense attorneys still invoke the North Carolina Supreme Court's 1988 Hennis ruling to limit the presentation of redundant photographs that could unduly influence jurors.
[6] In 2012, the Investigation Discovery series Unusual Suspects documented the case in the episode "Mother's Day Murders".
[18] In September 2014, the CNN crime documentary series Death Row Stories released an episode covering Eastburn family murders and trials of Hennis.