CHICAGO, Illinois (CNN) -- A man suspected of murdering a doctor in Chicago, Illinois, is trying to skirt the U.S. justice system by fleeing to the French island territory of St. Martin, according to prosecutors.
Dr. David Cornbleet, a dermatologist, was murdered in his Chicago office in October, 2006.
"He's doing everything possible to protect himself," said Bernie Murray, chief of criminal prosecution for the Cook County State's Attorney's Office in Illinois. "At the end of the day, he's making a mockery of both French law and United States law."
After fleeing to St. Martin, Hans Peterson, 29, turned himself in to French authorities and allegedly confessed to murdering Dr. David Cornbleet in October, 2006. Jon Cornbleet, Dr. Cornbleet's son, said he has seen a four-page confession in which Peterson admits to attacking and killing David Cornbleet in his Chicago office.
Despite the alleged confession, Peterson is beyond the reach of U.S. law enforcement. As a French national on French soil, he cannot be sent to the United States for trial, according to a 2002 extradition treaty between the two countries. The United States, by contrast, is allowed to extradite U.S. citizens to France, under the treaty.
U.S. Sens. Barack Obama and Dick Durbin, both of Illinois, sent letters to Secretary of State Condoleezza Rice asking for help extraditing Peterson. In response to the senators, the State Department wrote it "will continue to make every effort with the government of France to see that justice is served in this case."
Sens. Durbin and Obama also wrote the French government requesting extradition.
French Foreign Ministry spokesperson, Francois Rivasseau, responded "the French government will not be able to extradite Mr. Peterson."
"French laws provide in that case for trial on French territory by French justice," he said in a statement.
Murray of the Cook County State's Attorney's Office said he favors extradition over a French trial because he believes French laws are more lenient. He said a life sentence there is only 22 years. In Illinois, Murray said, murder is punishable by a minimum of 20 years in prison and possibly much more.
"It goes up to 60 or 80 or 100 years, possibly life, possibly the death sentence, depending on the facts surrounding the crime," Murray said.
Hoping to persuade the French to extradite Peterson, Murray and the Cornbleet family said they would not seek the death penalty in the case. There is currently a moratorium on the death penalty in Illinois.
According to the victim's son, Jon Cornbleet, Peterson first met Dr. Cornbleet in 2002 when he was living in Chicago and went to see him for an acne problem. His father prescribed a popular acne medication, which, according to Jon Cornbleet, Peterson said made him impotent. It is believed this is the only time the two met before the night of the murder.
Peterson's father, Dr. Thomas Peterson, said his son was an "okay kid who had a little depression." He said his son took just two pills, but that the acne medication made him psychotic.
Dr. Cornbleet's daughter, Jocelyn, found his body in his office. "I could see on the second closed door that there was blood across it," she told CNN. "I knew that somebody had killed him." Jon Cornbleet said his father was stabbed more than 20 times.
For months, the case went unsolved, even though authorities said there was DNA evidence at the scene. Then, over the summer, investigators got a tip from a U.S. Marine on leave from Iraq.
The Marine said a friend told him, "I think my former roommate killed someone." The Marine reached out to the Cornbleets through a posting they had made on myspace.com and also contacted Chicago police.
He told the Cornbleet family Peterson was living in New York around the time of the murder. The family believes Peterson drove from New York to Chicago, killed Dr. Cornbleet, and then drove back to New York, reportedly telling friends he had "completed his mission."
The Cornbleet family said video surveillance from Dr. Cornbleet's office building shows Peterson entering and leaving the premises on the night of the crime. Using the Marine's tip, DNA evidence and the surveillance video Chicago police got a warrant to arrest Peterson.
But before they could track him down, Peterson fled to St. Martin. So far, Peterson has yet to be charged with a crime. He is being held in jail on the French Island of Guadeloupe. The French government did not return CNN's phone calls for this story.
Jocelyn and Jon Cornbleet said they will continue to fight for his extradition.
"We're gonna go until there's absolutely nothing more we can do," Jocelyn Cornbleet said. "'Til we get justice." E-mail to a friend