Steven Brian Pennell

On September 14, 1988, Renée Tashner, an undercover police officer posing as a prostitute, roamed Route 40 in an attempt to capture the killer. After passing several vehicles, she spotted a blue Ford seven times in 20 minutes. She went to a more isolated area, and the vehicle stopped next to her. The driver was white, with Tashner noticing that the floor had a blue carpet. The man appeared nervous, hardly looking her in the eyes, but still attempted to convince her to enter the car. She refused, claiming that she was tired, but managed to tear some fiber from the blue carpet and write down the license plate number. Upon examination of several license plates, it emerged that the vehicle belonged to Stephen Brian Pennell, a 31-year-old electrician, married and father of two, with no criminal record.

Delaware public prosecutor Charles Oberly approved a police search warrant of the panel van, while at the same time searching for other offences for which they could arrest Pennell. While searching the vehicle, prints matching the blood and hair of the victims, as well as the same adhesive tape used in the DiMauro killing, were found. A "torture kit" was also found, which included pliers, whips, handcuffs, needles, knives and restraints. Pennell was arrested on November 29, 1988, a year after he murdered the first victim, and was charged with killing three - Ellis, DiMauro and Gordon. He decided to invoke his right to remain silent.

At the start of the trial, a panel of defense attorneys claimed that the initial fiber taken by Officer Tashner was obtained illegally, because it was taken from his car. Judge Richard Gebelein dismissed these allegations, saying that the carpet was visible to Tashner's eyes as soon as she opened the vehicle, so evidence from these fibers was legal. Once the fibers were examined, it was shown that they had DNA residues belonging to the victims. It was the first trial in the United States that used DNA evidence as absolute legal evidence. Gebelein had to set a legal precedent and listen to the opinions of experts and scientists, who helped verify the DNA evidence.

However, the strongest evidence against Pennell was the testimony of his lawyer, who decided to stop representing him because of the things he heard. He testified that Steven had told him how he picked up DiMauro, paid her for sex and then killed her. He added that his former client showed no remorse for his actions, and spoke without emotion. This testimony caused a great deal of shock among the jury. The psychiatrists ruled that Pennell's sanity was questionable, but he was still charged with three homicides. The jury deliberated for eight days, setting a record for longest hearing in Delaware legal history.

On November 23, 1989, the jury reached a decision and convicted Pennell of murdering DiMauro and Ellis, but acquitted him of Gordon's murder because of lack of evidence. The jury decided not to recommend the death penalty, but two life sentences. Shortly after the decision, a bouquet of flowers was sent to the prosecutor's office, with a note reading: "You made us feel human again, from the women of Route 40."

Pennell's lawyer appealed the court's decision on the grounds that the fiber was obtained illegally. The court dismissed it, and based on new evidence introduced in the case, convicted Pennell of murdering Gordon and Meyer.[2] At this point, Pennell dismissed his lawyer and asked to represent himself, a decision the court approved. In a surprising move, he announced that he wished to receive the death penalty. He argued that the entire constitution began with a verse from the Hebrew Bible, and as soon as the court found two witnesses who could testify to his guilt, he deserved the death penalty under the Bible's laws. He cited two passages from the Bible to explain his position.

On October 31, 1991, the court sentenced Pennell to death. Under the Delaware State Constitution, every death penalty judgment requires a further hearing from the Supreme Court, and on February 11, 1992, Pennell appeared before them, demanding that he be sentenced to death. He was the only defendant in Delaware's legal history to represent himself before the Supreme Court, and the only man convicted to willingly seek the death penalty.

However, he pled not guilty to the murders, and spoke of the murderer in the third person, saying that the killer was enjoying the process of the murder, but not the murder itself.[3] The Delaware State Attorney General objected to the death penalty, but the judges sentenced Pennell to death anyway. His execution was scheduled for March 14, 1992.

Two people appealed against Pennell's execution, but both were unanimously dismissed by the court. His wife, Vera Catherine Pennell, appealed the Supreme Court's decision. She received help from the local branch of the American Citizens Association, and a law professor who was one of its directors. He argued in his appeal that Pennell was insane and could not fully understand the gravity of his actions, so the trial should be reopened, with Pennell being barred from representing himself. The Supreme Court rejected the demand.

Prior to the execution, numerous reporters tried to ask Pennell for exclusive interviews, hoping to reveal the location of Meyer's body. He turned down every request. When it came close to his execution date, he agreed to be interviewed by one newspaper, with his lawyer present. During this interview, Pennell revealed no new information, nor where he had hidden Meyer's body.

On March 14, 1992, at 9:49 PM, Pennell was executed by lethal injection, becoming the first person executed in Delaware in 46 years, and the 165th person to be executed in the United States since the death penalty was reinstated in 1976.[4]

• List of serial killers in the United States